Password accepted, no login

[roog]

I recently installed Linux Mint 19 Cinnamon and it was working fine. Today when I try to log in, it just comes back with the password prompt. I found a previous post related to this and the proposed fix was to change the password. I did that but still get the same result. If I press Ctrl+Alt+F4 and log in, the password is accepted, but then how do I get the UI back?

[rene]

I expect you have home directory encryption set up? If yes, please see viewtopic.php?f=90&t=276445#p1518801

[roog]

Is home directory encryption the default? If not, then I don't have it set up.

If for some reason it is set up, then the problem occurred before the user password was changed, The thread you reference indicates that this can (only?) happen when home directory encryption is enabled AND the user password is changed using root.

[gm10]

It's not on by default. Try entering the password with the on-screen keyboard (accessed via the top panel). It's possible you're simply typing it incorrectly (due to unexpected keyboard settings maybe?).

[roog]

No, I'm not typing it incorrectly. Please read the last sentence of the OP.

Since I just installed Mint, I can reinstall without any problem. However, I would like to know what has caused this behavior, since it would be inconvenient if it happened again after I've used the system for awhile.

[gm10]

No, I'm not typing it incorrectly. Please read the last sentence of the OP.

Actually what I said was exactly because of your last sentence - you said the password is "accepted" only on the virtual console. So to clarify, when you log in at the graphical login screen, does it reject your password or does it accept it but bounce you back to the login screen regardless?

If it's the latter, there can be a number of reasons. One of them can be that one of your partitions is full. Switch to a virtual console Ctrl+Alt+F1, log in and run

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df

Check the "Use%" column that none of them are at or near 100%. If they are, that's your problem.

Alternatively it can be a permissions problem, run this:

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sudo chown -Rc $USER:$USER $HOME
rm ~/.Xauthority ~/.ICEauthority

The switch back to the graphical login screen with Alt+F7 and try your luck.

If that didn't work, switch back to the virtual console and run

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sudo mv $HOME $HOME.bak
sudo mkdir $HOME
sudo chown $USER:$USER $HOME
exit

Unless you messed your system up properly you will be able to log in now, albeit with a clean profile. Your previous profile still exists in /home with a .bak suffix.

[roog]

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Filesystem     1K-blocks     Used Available Use% Mounted on
udev             3999404        0   3999404   0% /dev
tmpfs             806156     1528    804628   1% /run
/dev/sda6      100267080 10198288  84932408  11% /
tmpfs            4030768        4   4030764   1% /dev/shm
tmpfs               5120        4      5116   1% /run/lock
tmpfs            4030768        0   4030768   0% /sys/fs/cgroup
/dev/loop0         90112    90112         0 100% /snap/core/5328
/dev/loop1        141440   141440         0 100% /snap/skype/54
/dev/loop2        144768   144768         0 100% /snap/skype/51
/dev/sda1	  507904    56664    451240  12% /boot/efi
tmpfs             806152       12    806140   1% /run/user/109
tmpfs             806152        0    806152   1% /run/user/1000

Did something get messed up when I installed/used Skype? It didn't happen right away. I installed Skype, used it, added another application, logged out, logged in and out a few times and then came the problem.

[gm10]

Did something get messed up when I installed/used Skype? It didn't happen right away. I installed Skype, used it, added another application, logged out, logged in and out a few times and then came the problem.

No, that's normal for loop devices. Mint doesn't use snapd as a software source by default so I didn't think to mention that. I don't believe snapd would be the reason for your troubles. Try the other options I mentioned.

[roog]

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sudo chown -Rc $USER:$USER $HOME

worked but

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rm ~/.Xauthority ~/.ICEauthority

failed, couldn't find file.

I could log in after that. A dialog popped up to say that the password no longer matched the keyring password, but I cancelled that. I assume this is from the fact that at one point during the trouble I did change the password. Does this have any repercussions?

I still would like to know what caused this problem. I also don't understand why the password was rejected by the GUI login but accepted by the console login.

Thanks for your help. As an experienced Windows user (and before that DOS and CP/M), I'm really having a struggle.

[gm10]

I could log in after that. A dialog popped up to say that the password no longer matched the keyring password, but I cancelled that. I assume this is from the fact that at one point during the trouble I did change the password. Does this have any repercussions?

Yes, that's exactly because of that, and we'll just have to fix that. If you don't have any passwords stored the fastest way is just to delete the keyring, log out and back in, it will be re-generated with the correct password then:

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rm -v ~/.local/share/keyrings/login.keyring

Otherwise we'll need to change the password on the keyring to match, I'll tell you how if needed.

I still would like to know what caused this problem. I also don't understand why the password was rejected by the GUI login but accepted by the console login.

It wasn't that your password was rejected (your misunderstanding about this is what caused my initial suggestion about the on-screen keyboard). Your password was fine, but the graphical environment couldn't be loaded successfully due to a permissions issue. So it basically failed-over to the login screen.

It's hard to give you an exact diagnosis for lack of data, but, for example, launching GUI applications with a sudo prefix is something that can cause this. Applications improperly run as superuser may change permissions or ownership on certain files, resulting in user-mode applications to be unable to access them.

The commands I gave you that did the trick changed ownership of all files in your profile folder back to your user account, and for good measure deleted two files that contain session authentication data so they would be re-created.

Thanks for your help. As an experienced Windows user (and before that DOS and CP/M), I'm really having a struggle.

Heh, I still know CP/M. Been a while. And you're welcome.