unable to launch "cinnamon-session-cinnamon" X session

[noodleindenial]

Linux Mint Cinnamon 21.2 Victoria amd64

Hope I'm posting this in the right place; please let me know if I should move it.

When logging in, I encountered the error:

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unable to launch "cinnamon-session-cinnamon" X session --- "cinnamon-session-cinnamon" not found; falling back to default session.

After closing the message, I was left with nothing but a cursor and a blank screen. Restarting did nothing. All three user accounts on the machine have this error. Nothing weird happens during boot (that I can see), and the login screen looks normal. Only after logging in does the error appear.

(To write this post I had to sift through a long output file from a script command and there were a lot of messed up characters in there. So bear with me if there are any typos or omissions.)

I pressed ctrl+alt+f1 to enter the fallback terminal. I ran sudo apt update, but it failed.

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Failed to fetch http://packages.linuxmint.com/dists/victoria/InRelease  Could not resolve 'packages.linuxmint.com'
Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy/InRelease  Could not resolve 'archive.ubuntu.com'
Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy-updates/InRelease  Could not resolve 'archive.ubuntu.com'
Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy-backports/InRelease  Could not resolve 'archive.ubuntu.com'
Failed to fetch http://security.ubuntu.com/ubuntu/dists/jammy-security/InRelease  Could not resolve 'security.ubuntu.com'
Some index files failed to download. They have been ignored, or old ones used instead.

--fix-missing didn't work either.

I verified that my connection and router were working with another machine. So I figured the sources list must have gotten messed up. cat /etc/apt/sources.list returned:

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#deb cdrom:[Linux Mint 21.2 _Victoria_ - Release amd64 20230711]/ jammy main

# This system was installed using small removable media
# (e.g. netinst, live or single CD). The matching "deb cdrom"
# entries were disabled at the end of the installation process.
# For information about how to configure apt package sources,
# see the sources.list(5) manual.

At first I thought the lack of sources meant this was the problem. But I did some research and, if I understand correctly, this is normal in Mint. So I ran cat /etc/apt/sources.list.d/official-package-repositories.list

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# Do not edit this file manually, use Software Sources instead.

deb http://packages.linuxmint.com victoria main upstream import backport #id:linuxmint_main

deb http://archive.ubuntu.com/ubuntu jammy main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu jammy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu jammy-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse

I've never edited this file directly, and this looks correct so I assume it's not the problem either.

Next I tried the ping command. No matter what server I pinged, I got ping: <url>: Name or service not known where "<url>" == the website I was trying to ping.

So I ran cat /etc/hosts:

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127.0.0.1	localhost
127.0.1.1	<name>

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Where "<name>" is the computer name (censored for privacy). It also matches the contents of /etc/hosts and the output of hostname, so this file seems correct to me too.

At this point I've accepted the fact that I might have to reinstall the OS, but I at the very least I want to figure out what went wrong so I can learn from this. I've only been using Mint for a few months, but it has a reputation as a mature and stable distro, so I assume this must have been my fault (right?).

But if I could get Cinnamon working again that would be great.

Anyway, my best guess is that this happened because I uninstalled a few packages the day before. Specifically, I removed bluetooth and libbluetooth3. That second one jumps out in particular because it showed up as a dependency when I tried to sudo apt install mint-meta-cinnamon. (This install failed too, of course.)

Another possibility is that this has to do with a crash that happened about a week before this error. I was running a flatpak update and using a USB switch (like a KVM switch but with only USB) to use a different machine. But at some point my Mint machine stopped responding and stopped sending output to the monitor. I had to hard shut it down. But it ran fine after that, booting several more times with no apparent problems before the big error. It seems like the USB switch might have been the culprit here; the other machine had weird visual bugs whenever I switched to it (but it didn't crash).

The only other thing I can think of: A couple times in the past few months, Cinnamon crashed in the middle of use (not when starting). But it was much less severe. The fallback GUI actually worked, and logging out and back in fixed it. So I assumed these bugs were small edge cases and didn't think anything of it.

Any suggestions as to what might have gone wrong or how to fix Cinnamon would be greatly appreciated.

[gittiest personITW]

Welcome to the forums.

Try this:

Ctrl+Alt+F1
Then type the following lines, 1 at a time. Press enter. Then the next line.

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sudo apt-get install mint-meta-cinnamon
sudo reboot

If that doesn't work, did you create Timeshift snapshots?

[noodleindenial]

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sudo apt-get install mint-meta-cinnamon
sudo reboot

I tried that before, and did it now just to be sure. Any apt update or apt upgrade fails. Every source has a "failed to fetch... could not resolve" error. I checked the network and I checked the sources files. (The contents of the sources files are in the original post.)

I also tried ping, and that doesn't work either. So I checked /etc/hosts and that looks fine too. (You can check the post if you want to see it.)

Unfortunately I didn't set up Timeshift. Certainly wish I had.

[SMG]

Unfortunately I didn't set up Timeshift. Certainly wish I had.

Have you tried Lord Boltar's solution here?

[Giolinux]

https://owlhowto.com/how-to-fix-unable- ... -cinnamon/

[Crumbs350]

I have a similar issue to the original poster and adding possible symptoms and bandaid that may help maintainers or others with issue. Fresh 21.2 install with updates run. Roughly third boot see black screen issue on boot (no GUI and no console). I'd seen this issue on prior 20.3 install where sometimes with black screen you could type password and the GUI would appear, did not work in this case.

Symptoms

• I notice this issue more with display port cable than hdmi cable monitor connection

• issue occurs more if monitor is not turned on when PC boots

Bandaid Solution

• as others have suggested using CTRL+ALT+F1 to drop to console works. you can login and type

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  startx

  to load the GUI

Even though I have a relatively fresh install I've give Lord Boltar's suggestion a try.