Solutions for some bugs in Linux Mint 20


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No operating system is flawless. Linux Mint is no exception.

Here you'll find solutions for some bugs in Linux Mint 20 (or in the applications that are part of a default installation of Linux Mint).

Contents of this page:

Can't boot from install DVD: processor without PAE support

1. Does your computer have an old processor without PAE support? For many non-PAE processors from the Intel Pentium M series and Intel Celeron M series, PAE support can be forced. Which makes them fit for Linux Mint after all.

You can force PAE upon such a processor by selecting Start with PAE forced in the boot menu from the Mint DVD. You can make that boot menu visible by interrupting the automatic boot, by hitting the space bar during the countdown.

Computer won't boot after installation of Mint

2. Some computers, after a seemingly flawless installation of Mint, won't boot. I'll describe two situations here.

a. You see the following error, in white letters on a black screen:

error: unknown filesystem
grub rescue>

In that case you've probably used an USB memory stick for the installation (Live USB). It happens sometimes, that the memory stick identifies itself as sda and the hard disk as sdb. And that's how it configures bootloader Grub then, during the installation!

After the installation bootloader Grub wants to boot from sdb, but sdb has disappeared: the hard disk should be addressed as sda now. The installer has therefore correctly installed and configured everything for sda, except for.... Grub.

In that case it suffices to redirect Grub to sda, which you can do as follows. The easiest method is when you use a Mint DVD for that, because then you can be sure that there will be no new switching of sda into sdb in the live session.

When you don't have the option to use a DVD, then you might try a Live USB of Xubuntu 20.04 LTS, because that one probably has no switching problem (at least in my limited experience).

b. In another situation you may see one of these two errors, in white letters on a black screen:

error: invalid arch independent ELF magic.
grub rescue>

Or this error:

error: file '/boot/grub/i386-pc/normal.mod' not found.
grub rescue>


In that case the cause may be, that Mint has installed a wrong kind of boot loader. Namely Grub for EFI / UEFI (grub-efi) instead of the ordinary Grub for BIOS.

Among others, this happens on a Lenovo B570e laptop. Although this computer has a UEFI and not a BIOS, this UEFI has been configured by Lenovo to behave as if it were a BIOS. That's why it needs the ordinary Grub for BIOS.

Reparation is then pretty simple: install the ordinary Grub with the Mint DVD.

Computer boots straight into Windows 8.x or 10, after dual boot install

3. In certain cases, after an apparently successful installation of Mint next to an existing Windows 8.x or 10, your computer might boot straight into Windows 8.x or 10. No boot menu then, in which to select Mint.

This might be caused by a wrong boot priority order in the UEFI. If so, you can fix it like this (item 2.2).

The installation of Mint can't be finished: it fails halfway

4. Especially on older computers, it might happen that the installation of Mint suddenly fails. This could be caused by the slideshow.

During the installation of Mint you see a slideshow, with beautiful pictures about what to expect in your new Mint. But sometimes this slideshow creates problems: the graphics card can't handle it, because the right driver hasn't been installed yet, and the installation stalls.

In that case you can remove the slideshow like this:

Launch a terminal.
(You can launch a terminal like this: *Click*)

Use copy/paste to transfer the following command line to the terminal:

sudo apt-get remove ubiquity-slideshow-*

Press Enter.

After the removal of the slideshow you can launch the installer again.

Swap use (swappiness) is too high: Mint is too slow and uses the hard disk too much

5. This is especially noticeable on computers with relatively low RAM memory (2 GB or less): they tend to be far too slow in Linux Mint, and Mint accesses the hard disk too much. Luckily, this can be helped.

Note: does your computer have 8 GB RAM or more? Then you can skip this item, because with so much RAM you probably won't notice any benefits from applying it.

On the hard disk there's a separate file or partition for virtual memory, called the swap. When Mint uses the swap too much, the computer slows down a lot.

Mint's inclination to use the swap, is determined by a setting called swappiness. The lower the setting, the longer it takes before Mint starts using the swap. On a scale of 0-100, the default setting is 60. Which is much too high for normal desktop use, and only fit for servers.

A detailed explanation can be found here (link dead? Then download this pdf file with the same content).

Now the how-to:

a. Check your current swappiness setting:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (use copy/paste):

cat /proc/sys/vm/swappiness

Press Enter.

The result will probably be 60.

b. Then type in the terminal (use copy/paste):

xed admin:///etc/sysctl.conf

Press Enter.

Scroll to the bottom of the text file and add your swappiness parameter to override the default, so copy/paste the following two blue lines:

# Decrease swap usage to a more reasonable level
vm.swappiness=10

c. Save the text file and reboot your computer.

d. After the reboot, check the new swappiness setting:

Launch a terminal and type (use copy/paste):

cat /proc/sys/vm/swappiness

Press Enter.

Now it should be 10.

Note: if your hard disk is an SSD, your machine will benefit from an even bigger decrease in swappiness. That's because too many write actions, like frequent swapping, reduce the lifespan of an SSD. For an SSD I advise a swappiness of 5. Also check these tips for optimizing an SSD for your Linux.

Black screen after installation of the closed non-free Nvidia driver

6. When your computer boots into a black screen after you've installed the closed proprietary Nvidia driver for your video card, this is often a solution.

The screen resolution is not right, after installation of the closed non-free Nvidia driver

7. Note: the following applies only to Nvidia graphics cards running on the Nvidia restricted driver.

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (or copy/paste):

sudo apt-get install nvidia-settings

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

b. Then type in the terminal (use copy/paste):

nvidia-settings

Press Enter.

Now you can configure your screens properly, with this handy tool from Nvidia. As follows:

- Click on "X Server Display Configuration" (in the upper left)

- On the right: click on the tab Display (probably open already)

- Resolution:click on the arrow after "Auto"

- Choose the screen resolution that you want

- Click on "Save to X Configuration File"

- Click on "Save and exit"

- Do a full reboot of your computer. Now the screen resolution should be right.

The tools for updating or installing software malfunction

8. It can happen that the tools for updating or installing software (Update Manager, Software Manager or Synaptic Package Manager) malfunction, although you do have internet connection. The cause is usually a problem with the software lists.

In that case, you often see an error report with (among other things) this text:
E: encountered a section with no package: header
E: problem with Mergelist/var/lib/apt/lists


You can solve this very easily: from the menu, launch Software Sources. Then click on the button Maintenance and then on the button Fix MergeList problems.

Ubuntu: in Ubuntu you have to do this:

a. First remove the old lists:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (use copy/paste):

sudo rm /var/lib/apt/lists/* -vf

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

b. Now retrieve the new lists from the internet:

In the terminal (use copy/paste):

sudo apt-get update

Press Enter.


The problem should be over now.

Reboot fails

9. Some laptops won't reboot. The computer simply "hangs" after a rebooting attempt.

In most cases this has to do with BIOS and (U)EFI. You can remedy it as follows:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Then type in the terminal (use copy/paste):

xed admin:///etc/default/grub

Find the line:
GRUB_CMDLINE_LINUX=""

...and replace it by this line:
GRUB_CMDLINE_LINUX="reboot=efi"

Save the changes and close the file.

c. Now issue this command in the terminal (use copy/paste):

sudo update-grub

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

Now shut your computer down (no reboot!). Turn it on again, and after logging into your user account, try to reboot it. This should work now.

Hibernate and suspend don't always work well: they make some computers malfunction or even enter a coma

10. "Hibernate" and "suspend" still cause problems on some hardware, and unfortunately.... for much hardware there is no solution yet, because most manufacturers of BIOS and UEFI don't stick to the standards for implementing power saving.

Therefore it's better to turn off one or both of these sleep modes, if they don't work well on your computer.

"Hibernate" (suspend-to-disk) is the most agressive of the two sleep modes, which is why it causes problems more often than "suspend" (suspend-to-ram). If "suspend" does work well on your machine, you don't have to disable it, of course.

Both in Linux Mint and Ubuntu, "hibernate" is therefore disabled by default, but "suspend" is enabled by default. Which I think is a reasonable compromise.

Disable suspend (suspend-to-ram)

10.1. You can disable suspend (suspend-to-ram) as follows (only do it when really necessary, because it's generally a useful feature):

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Copy/paste the following line into the terminal (make sure to use copy/paste in order to prevent typo's, it's one line!):

sudo touch /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla

Press Enter.

c. Copy/paste the following line into the terminal (use copy/paste to prevent typo's, it's one line!):

xed admin:///etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla

Press Enter.

d. Copy and paste the following blue text into that empty text file:

[Disable suspend (upower)]
Identity=unix-user:*
Action=org.freedesktop.upower.suspend
ResultActive=no
ResultInactive=no
ResultAny=no

[Disable suspend (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend
ResultActive=no

[Disable suspend for all sessions (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend-multiple-sessions
ResultActive=no

Save the text file and close the text editor.

e. Reboot your computer (full reboot). Suspend should now no longer be one of the options in the shutdown menu.

f. On a laptop, it's advisable to check the power manager settings: you'll have to find alternatives for suspend, for actions like closing the laptop lid.

How to undo

10.1.1. Do you want suspend back? The above hack is easily reversible. Undoing it is very simple:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Copy/paste the following line into the terminal (it's one line):

sudo rm -v /etc/polkit-1/localauthority/90-mandatory.d/disable-suspend.pkla

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

Reboot your computer. The suspend option should be back now.

Workaround for a FIDO U2F Security Key

11. There are several manufacturers that produce a USB key for two-factor authentication, like for example Yubico with its Yubikey. Such a key is handy and secure.

Because of a usability regression, you probably have to configure Ubuntu and Linux Mint for the use of a FIDO U2F Security Key. Like this:

a. Install the latest Google Chrome, because that web browser is currently the best for using such a key. The Chrome installation package for Ubuntu and Mint is a .deb file, so you can simply double-click it in order to install Chrome.

b. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

c. Copy/paste the following line into the terminal (make sure to use copy/paste in order to prevent typo's!):

sudo apt-get install libu2f-udev

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

d. Reboot.

e. Launch Google Chrome and install the key, for example for your Gmail account.

f. No avail? Then try a manual approach, starting with this terminal command:

sudo touch /etc/udev/rules.d/70-u2f-generic.rules

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

g. Now open that text file for editing, with this command line (use copy/paste to transfer it into the terminal):

xed admin:///etc/udev/rules.d/70-u2f-generic.rules

Press Enter.

h. Empty all existing contents (if any) and copy/paste the following blue text into it (don't type it!):

ACTION!="add|change", GOTO="u2f_end"

KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="*", ATTRS{idProduct}=="*", TAG+="uaccess"

LABEL="u2f_end"


i. Save the modified file and close it.

j. Reboot your computer.

k. Launch Google Chrome and install the key, for example for your Gmail account.

The closed non-free Nvidia driver won't load

12. In certain rare cases, the closed proprietary graphics driver from Nvidia won't load, although you've installed it by means of Driver Manager (and rebooted afterwards). The old open-source Nouveau driver is still in use then....

In such a case, the window of Driver Manager looks approximately like this (click on the image to enlarge it):


When that happens, this might help:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Copy/paste the following line into your terminal:

xed admin:///etc/modprobe.d/blacklist.conf

Press Enter.

c. In that text file, add the following three blue lines at the bottom of the existing text (use copy/paste):

# Make sure that the installed non-free Nvidia driver is being used,
# instead of the default open-source Nouveau driver.
blacklist nouveau


Save the modified file and close it.

d. Copy/paste the following command into the terminal:

sudo update-initramfs -u

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

e. Reboot. The Nvidia driver should now be in use, which you can check by executing the following terminal command:

inxi -G

Some laptops: hard disk constantly clicks and spins up and down

13. Some laptop hard disks have a serious problem: they keep constantly clicking and spinning up and down. Not all laptop hard disks have this problem: it depends on the brand and model.

The cause is the firmware of the disk: its power management feature has been implemented far too agressively by the manufacturer. This is very unhealthy for the disk and may shorten its lifespan considerably.

Some operating systems contain a built-in correction for this firmware error, but many types of Linux don't.

The solution is not too difficult:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (use copy/paste):

sudo hdparm -B 254 /dev/sda

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

Now the nasty clicks should stop.

With this command you don't entirely disable the power management of the disk, but you limit it to a minimum. Positive side effect: your laptop becomes a little faster.

The "price" you pay is a somewhat higher power consumption, and therefore a slightly decreased battery time. But not much.

The command is for the current session only. If you want to make it permanent, you can do this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Then type in the terminal (use copy/paste):

xed admin:///etc/hdparm.conf

Press Enter.

Now text editor Xed opens a text file. Add the following blue text, at the very end of the existing text (use copy paste to avoid errors):

/dev/sda {
    apm = 254
    apm_battery = 254
}

c. Save the file, close Xed and reboot your computer (full reboot).

d. Finally, disable hibernate and suspend, because the hard disk will start clicking again after waking up from those (see item 10 on this page).

This is actually no fault of Mint, but of the hard disk manufacturer, who provides bad firmware.... It's not good when an operating system has to correct a firmware fault.

Wireless internet is sometimes being blocked by Bluetooth

14. On some laptops, wireless internet (wifi or 3G) is being blocked by Bluetooth. In that case, the solution is simple: temporarily disable Bluetooth, by clicking on the bluetooth icon in the upper panel. Then reboot your laptop. Bluetooth should remain disabled and you should be able to make wifi or 3G connection.

If Bluetooth should be enabled again after reboot, disable it more thoroughly by disabling it in the BIOS of your laptop.

Large PDF documents can't be printed entirely

15. The default PDF reader in Mint (xreader) sometimes has difficulty handling large PDF documents, which may cause printing failure.

To work around this problem, you can use a lightweight alternative PDF reader called xpdf. Unlike its bigger brother, xpdf has no difficulty printing large PDF documents.

You can install xpdf with a few mouseclicks in the application Software Manager, because it's present in the default software repositories of Mint.

File Manager Nautilus might be installed as unwanted extra

16. When installing certain applications that have file manager Nautilus as "recommended" dependency, you get Nautilus into the bargain!

That's undesirable, because installing a second full-blown file manager like Nautilus alongside your default file manager, will lead to conflicts. When you suddenly find that you've got Nautilus in your menu, I advise to remove Nautilus immediately, like this:

sudo apt-get remove nautilus

This should leave all other installed applications intact, including the one whose installation pulled Nautilus. So it should always be safe to remove Nautilus.

Can't launch any web browser

17. On some old computers you can't launch any web browser (Firefox, Chrome, Chromium, ...), because the CPU doesn't support sse2. That support is required for the current versions of those browsers.

This is how you can check whether your CPU supports sse2:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (use copy/paste):

cat /proc/cpuinfo | grep sse2

Press Enter.

In the output you should find sse2 in red text. If you don't get any output at all, then unfortunately you can't use a web browser on that machine.

Note: some how-to's advise in such a case, to install an older version of your web browser, that doesn't require sse2 support. Don't do that!

Your web browser is, by far, the most heavily attacked application in your system. Most of the malicious software on websites, targets web browsers. So it's absolutely unsafe to use an older version of your web browsers, also in Linux.

The size of the log files in /var/log gets out of hand

18. Thankfully it's a rare problem, but anyway: some errors create huge log files in the folder /var/log, causing rapid loss of disk space. When you have this problem, you should of course fix the underlying error(s) as soon as possible.

In order to read the gigantic log files you'd better not use a normal text editor, because it'll probably be bogged down by the sheer size of the file. Use a terminal command instead, and only for the latest entries. Like this:

An example is easiest. For examining the log file /var/log/syslog, you do this:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Copy/paste this command into the terminal:

tail -100 /var/log/syslog > disk_eater.log

(of course you should replace syslog by the name of the actual log file that you want to examine)

Press Enter. That way you've created a small text file, called disk_eater.log, which contains the last 100 lines in the log file. It's in your personal folder. You can simply double-click it to read its contents. This should enable you to find the culprit, because it's the error messages denouncing the culprit that have flooded the log.

As emergency measure you can also limit the size of the log files, which you can do as follows:

a. First remove most log files like this:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Copy/paste the following line into the terminal:

sudo rm -v /var/log/*log*

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

b. Now limit the logs for the future like this (item 11).

c. Reboot and check the available disk space again.

Don't forget to solve the underlying problem! That should have a high priority.

Booting takes a very long time

19. On some hardware, booting lasts extremely long. You can try to find the cause of a slow boot as follows:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Copy/paste the following line into the terminal, to avoid errors:

systemd-analyze blame

Press Enter.

Sometimes the Network Time Protocol (NTP) is the culprit. If it's ntp.service that's eating all that time, you might try this:

Type (copy/paste to avoid errors):

sudo systemctl disable ntp

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

The price you pay for disabling NTP, by the way, is that your system time is no longer being synchronized with NTP servers. This is usually only a minor inconvenience.

Do you want to undo this? That's easy:

sudo systemctl enable ntp

A few graphics cards: disable hardware acceleration in your web browser

20. Hardware acceleration is on by default in Firefox and Chrome. Which is generally a good thing, because it should make rendering video's smoother. However, when you experience graphics problems in those web browsers (delay when typing text, problems with displaying video's), you can try whether it helps if you disable hardware acceleration as follows:

Firefox:
Click on the button with three horizontal dashes in the top right corner - Preferences - Performance:
remove the tick for: Use recommended performance settings
then remove the tick for: Use hardware acceleration when available.
Close Firefox and launch it again.

Chrome:
Click on the button with three dots in the top right corner - Settings - Advanced
section System: remove the tick for: Use hardware acceleration when available.
Close Chrome and launch it again.

Repair an Xfce desktop that suddenly looks weird

21. In case of an Xfce desktop (Linux Mint Xfce) that has suddenly started to look weird, you can try three things.

a. First the action with the least impact, namely a restart of the window manager.

- Launch a terminal window.
(You can launch a terminal window like this: *Click*)

- Copy/paste the following line into the terminal, to avoid errors:

xfwm4 --replace

Press Enter.

b. Disable all visual effects. In Linux Mint, even lightweight champion Xfce has some relatively heavy visual effects by default. Disable them like this:

Menu button - Settings - Desktop Settings
Window Manager: set it to plain Xfwm4 (instead of Xfwm4 + Compositing)

Then remove Compiz:

Launch a terminal window.
(You can launch a terminal window like this: *Click*)

Type (use copy/paste to prevent errors):

sudo apt-get remove compiz-core

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

c. If all that doesn't help, reset your Xfce desktop to its default settings as follows:

- Copy/paste the following line into the terminal:

rm -r -v ~/.config/xfce4

Press Enter.

- For the new settings to take effect, log out and log in again.

Make your login window (LightDM) show a nice background instead of eternal night

22. In Linux Mint, the feature of LightDM which enables you to set a nice background for it, may have a bug. Which in some cases causes the login window to have an ugly black background. This is how to work around that:

a. From the menu, launch the application Login Window.

b. Disable Draw user backgrounds (set the slider to off).

Then, in Background, select a static system background from /usr/share/backgrounds. I recommend to look for one in the folder /usr/share/backgrounds/linuxmint-tara, because that contains many beautiful images.

c. Close Login Window and reboot your computer. Now the login window should present you with a nice background.

Update Manager couldn't download all repository indexes

23. Occasionally, you might get this warning from Update Manager:
Could not download all repository indexes

With this further explanation:
An error occurred during the signature verification. The repository is not updated and the previous index files will be used.
Plus some complaining about a missing public key (NO_PUBKEY).

This might happen occasionally, when a repository maintainer changes the verification key of the repository. This means that you should load a new verification key into your system, otherwise you won't get updates for the packages that you've installed from that repo.

Google has been known to create such "key havoc" for the repository for its web browser Google Chrome. If it's Google that's plaguing you like this for Chrome, you can solve it by downloading a new key like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Use copy/paste to transfer the following command line into the terminal (it's one line!):

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

That should fix it. At least until the next key change....

Computer clock time shifts between Windows and Linux Mint

24. Windows stores the time on the hardware clock as local time. Linux Mint on the other hand, stores it as UTC (formerly: Greenwich Mean Time). This causes annoying clock problems on dual boot machines: the time keeps shifting.

It's easiest to make Linux Mint behave like Windows does, because Windows is more difficult to tame. It's actually a pity, because UTC makes more sense. Especially if you move your machine between time zones.

Below I describe two alternatives: the way to fix Windows (recommended, but slightly more difficult) and the way to modify Linux (not the best solution, but easier to apply). The choice is yours:

Alternative 1: setting Windows to UTC (recommended)

24.1. Want to tame Windows, even though it's slightly difficult? Right you are, because that's the most elegant solution. This is how:

Launch Regedit (Registry Editor) and click your way through to the following "directory":

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation\

In that "directory", create a new value, in the following way:

Right-click with your mouse on an empty white part of the Registry Editor window -
New - DWORD (32-bit) Value

(even in 64-bit Windows you have to select 32-bit DWORD here)

Give the new value the following name:

RealTimeIsUniversal

Press Enter to confirm the name.

Then double-click the new value and set its Value data to 1.

By default, Base should be set to Hexadecimal, which is what you want.

Click OK and close Registry Editor.

You're done! Now there's no need to modify your Linux.

Alternative 2: setting Linux to local time

24.2. Don't do this when you've already modified Windows as described in item 24.1!

This is how to make Linux behave in the inferior Windows way, so your time won't shift any more on your dual boot machine:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Use copy/paste to transfer the following command line into the terminal:

timedatectl set-local-rtc 1

Press Enter.

That should do the trick.

c. Check the status like this:

timedatectl status

Press Enter.

How to undo local time in Linux (back to UTC)

24.3. Want to undo local time for your hardware (go back to the superior default way of Linux Mint)? That's easy as well. Simply use this terminal command:

timedatectl set-local-rtc 0

Random freezes on Intel-based computers

25. On certain hardware combinations with Intel CPU's, you can experience random freezes of your system. In particular the Bay Trail series of Intel CPU's is known to be affected by this.

This can often be solved by sharply reducing the maximum sleep state of the CPU when idle (maximal C-state). Namely from 6 (or 9) to 1.

The price you pay for that is some extra power consumption, which is of course rather annoying for laptops (you'll notice a somewhat higher battery drain speed). But at least your machine should run stable now.

Proceed like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. First check your current max C-state. Use copy/paste to transfer the following command line into the terminal:

cat /sys/module/intel_idle/parameters/max_cstate

Press Enter.

The output will probably be 6 or 9.

c. Now copy/paste the following line into the terminal, in order to edit a settings file:

xed admin:///etc/default/grub

Press Enter.

d. Delete this existing line:

GRUB_CMDLINE_LINUX=""

Replace it by this line (use copy/paste to transfer it):

GRUB_CMDLINE_LINUX="intel_idle.max_cstate=1"

e. Save the changes and close the modified file.

f. Then execute this command line in the terminal:

sudo update-grub

g. Reboot.

h. Check the change with this command:

cat /sys/module/intel_idle/parameters/max_cstate

The output should be 1 now.

Boot error concerning the unpacking of initramfs

26. You might get to see the following error during booting, which is a bug:

Initramfs unpacking failed: Decoding failed

If you have a clean fresh installation of Mint 20 (no upgrade from 19.x), you'll probably be plagued by this bug. Check the system logs if you're unsure.

You should be able to solve this bug by changing the unpacking method from lz4 into gzip (like it was in Mint 19.x and Ubuntu 18.04.x), namely like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Copy/paste the following line into the terminal (it's one long line, don't chop it up):

sudo sed -i 's/COMPRESS=lz4/COMPRESS=gzip/g' /etc/initramfs-tools/initramfs.conf

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

c. Now copy/paste the following line into the terminal:

sudo update-initramfs -u

Press Enter. This is a resource-intensive job for your computer; wait patiently until it's finished.

d. Reboot your computer. The error should be gone now.

Fix system freezing trouble with AMD Ryzen CPU's

27. You might experience system freezes with AMD Ryzen CPU's. This might be a way to work around that:

I. First of all, in your BIOS (UEFI) configuration, find the following setting:
PSU Idle Control

Change it to:
Typical Current Idle

That should cure at least one type of Ryzen freeze problems.

II. Update the AMD firmware blob by updating the linux-firmware package to the latest version. Like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Copy/paste the following blue command line into the terminal (it's one huge line):

apt install git && git clone git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git && sudo cp -v -u linux-firmware/amdgpu/* /lib/firmware/amdgpu && sudo update-initramfs -uk all

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

III. Now you're going to pass an extra parameter to Grub. As follows:

a. Copy/paste the following blue line into the terminal:

xed admin:///etc/default/grub
(the three consecutive dashes are no error but intentional)

Press Enter.
(Ubuntu: replace xed by gedit)

b. Find the following line:

GRUB_CMDLINE_LINUX=""

In that line, copy/paste the following parameter between the quotation marks:

idle=nomwait

So that it becomes:
GRUB_CMDLINE_LINUX="idle=nomwait"

c. Save the modified configuration file and close it.

d. Then run in the terminal (note the dash in the command!):

sudo update-grub

IV. Reboot. Your AMD Ryzen machine should run more stable now.

There are also some other possibilities to address this issue, but those are hardware-specific and therefore not fit for a generic approach for all AMD Ryzen CPU's.

Repair a key server error for the Google repository

28. Did you install software like Google Chrome or Google Earth? Then you've also added the software repository of Google to your sources list. Which is fine, but once in a while, that Google repository tends to start complaining about a missing key. This also affects Update Manager.

If that happens, you can often simply wait until Google fixes that hiccup on its servers. But you should also be able to fix that yourself, by downloading that key again. Like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Use copy/paste to transfer the following command line into the terminal (it's one line!):

wget -q -O - https://dl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

c. You should get to see an "OK" message as output. Launch Update Manager and refresh it; it should spawn no errors anymore.

The Grub bootloader menu suddenly isn't hidden anymore upon booting

29. Once in a while, bootloader Grub may suddenly start showing its menu upon booting, even though it always was hidden. In that case, try if it helps when you poke Grub a bit:

You might be able to kick Grub out of its obviously buggy lethargy, by setting it to show the menu for an unnoticeable 0.1 second. Thus at last producing the desired effect (namely being hidden). This workaround has worked for me, in similar circumstances.

Proceed as follows:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Use copy/paste to transfer the following blue command line into the terminal:

xed admin:///etc/default/grub

(the three consecutive dashes are no typo but intentional)

Press Enter. Type your password when prompted (you'll be prompted twice).

c. Find the line:
GRUB_TIMEOUT_STYLE=hidden

Change it to:
GRUB_TIMEOUT_STYLE=menu

d. Then find the line below:
GRUB_TIMEOUT=0

Change it to:
GRUB_TIMEOUT=0.1

e. Save and close the modified text file.

f. Use copy/paste to transfer the following blue command line into the terminal:

sudo update-grub

(if you type: note the dash between update and grub!)

g. Reboot and test whether the Grub menu stays properly hidden this time.

Xfce edition: the Fn keys can't control the display brightness of your laptop

30. Do you have the lightweight Xfce edition on your laptop? Then Xfce's Power Manager might need to be configured to allow the Fn keys of your laptop to control the display brightness.

That can be achieved like this:

a. Menu button - Settings - Settings Editor. Make it full screen, so you can operate it easily.

b. In its left panel, click on xfce4-power-manager.

In its right panel, tick (enable) the value for:
handle-brightness-keys

c. Close Settings Editor.

d. Reboot (or log out and in again).

Problems with your touchpad? Change the driver

31. Does the touchpad of your laptop misbehave? Then try a driver change. Proceed like this:

a. Launch a terminal window.
(You can launch a terminal window like this: *Click*)

b. Use copy/paste to transfer the following command line into the terminal:

sudo apt-get install xserver-xorg-input-synaptics

Press Enter. Type your password when prompted. In Ubuntu this remains entirely invisible, not even dots will show when you type it, that's normal. In Mint this has changed: you'll see asterisks when you type. Press Enter again.

c. Reboot your computer.

Official bug lists for Linux Mint and Ubuntu

32. When you have a problem, read both the official bug lists for Linux Mint itself and for the Ubuntu it was built on. These lists can be found here (look for the header "Known issues" or "Known problems"):

Bug list for Linux Mint 20 Cinnamon

Bug list for Linux Mint 20 MATE

Bug list for Linux Mint 20 Xfce

Bug list for Ubuntu 20.04


Want more tips?

Do you want more tips and tweaks? There's a lot more of them on this website!

For example:

Speed up your Linux Mint!

Clean your Linux Mint safely

Avoid 10 fatal mistakes


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