Unmet dependencies. Libc6 The package system is broken

Question

Whenever I try to upgrade or install a new package i get the following

ibc6-dbg: Depends: libc6 (= 2.31-0ubuntu9.2) but 2.31-0ubuntu9.1 is installed \
libc6-dev: Depends: libc6 (= 2.31-0ubuntu9.2) but 2.31-0ubuntu9.1 is installed \
           Depends: libc-dev-bin (= 2.31-0ubuntu9.2) but 2.31-0ubuntu9.2 is installed
libc6-i386: Depends: libc6 (= 2.31-0ubuntu9.2) but 2.31-0ubuntu9.1 is installed

I've tried apt --fix-broken install
I've tried sudo apt-get -f install to force install.
I get the same error messages in both cases.

I'm still new to Linux and would love to learn how to fix these issues without wiping the os and reinstalling

Solution 1

I had similar issue on freshly installed Ubuntu 20.04.2 desktop 64bit, the difference is that libc6 ...9.3 was installed but my packages (g++ build-essential etc) could not be installed beceause libc6-dev could not be installed because it required libc6 ...9.2 which was older then the one installed

 libc6-dev : Depends: libc6 (= 2.31-0ubuntu9.2) but 2.31-0ubuntu9.3 is to be installed

So I just downgraded libc6 (and libc-bin too, because it seems very related to me) to version 2.31-0ubuntu9.2 this way:

sudo apt install libc6=2.31-0ubuntu9.2 libc-bin=2.31-0ubuntu9.2

Now my packages could install :) so it seems to work, let's see if we don't have much problems - but I guess not because this is a tiny change in libc (on the other side libc is very important)

BUT I DON'T KNOW WHAT WILL HAPPEN IN THE FUTURE:

• Will it in future updates hold this package fixed to still old version?
• Does anyone know how to unfix this version?
• Even if I could somehow unfix it from this version, then will ubuntu have this issue in the future?
• Does anyone know if it is some bug in Ubuntu packaging repository? I repeat: this was on a totally fresh Ubuntu 20.04 desktop

Some other places to look for inspiration:

• https://serverfault.com/a/993629/445123
• https://serverfault.com/a/1005063/445123

Solution 2

I would like to add to the answer of Tomeg, that downgrading with aptitude helped me to keep my packages depending on libc6 installed. When downgrading with:

sudo apt install libc6=2.31-0ubuntu9.

apt would also uninstall all my packages depending on libc6.

The following packages will be DOWNGRADED:
  libc6
0 upgraded, 0 newly installed, 1 downgraded, 206 to remove and 0 not upgraded.

As I described here this did help since aptitude offered me different options:

 sudo aptitude install libc6=2.31-0ubuntu9.2

I had to decline the first two options (2x n) and then the third was to solely downgrade (y) without uninstalling other packages.

Comments

[Admin]

Please edit your question to show the complete output of sudo apt update and then of sudo apt upgrade

[Admin]

As user535733 has said; you likely had warnings in your sudo apt update output, OR it provides clues as to a problem. A quick scan of the packages expected and I see 9.2 matching your =9.2 for libc6-dbg, so it could be the source isn't showing or error in sudo apt update, or your used mirror isn't up-to-date and needs checking (you start with sudo apt update detail as you update your software lists on your hardware) etc...

[Alex Savenko]

Man, you nailed it. Thanks!

[Vincent Gerris]

can you please file a bug on launchpad? I had a similar issue. got too much invested in setup now to potentially break - it seems like a wrong dependency declaration in packages - UPDATE : bugs.launchpad.net/ubuntu/+source/glibc/+bug/1926918 seems this is tracked.

[peterretief]

I am really not happy doing this but it works for now.

[moralejaSinCuentoNiProverbio]

Thank you. With this command I could downgrade lib6 and install build essential.

[Humpity]

Thankyou. The number of apps to be uninstalled nearly gave me a heartattack. Why can't these repositories keep in sync ?