cinnamon lockscreen stuck in wrong password loop

[pste]

Hi all!

I'm actually not sure this is cinnamon desktop related, could be pam or something else...

And, I feel I've experienced this some years ago, and think there was a simple fix like just deleting some stray log or lock files, but cannot seem to find my way back to exactly what files! So, does anyone have a clue about where to start digging?

The problem is, when the lock screen has been active for some time (a rough guess is 10 minutes), or after being activated as a consequence of putting the system to sleep, it is impossible to unlock. The lock screen appears stuck in an endless loop where a wrong password already has been entered (even without trying to do so). It states something like "wrong password - account will be locked in x minutes". But if a new attempt to enter the password, the screen just "shivers" and the error message reappears. After rebooting, login works normally.

If the screen is manually locked, it is possible to unlock as usual within a certain time frame (probably the same as the estimated 10 minutes above). Maybe the time coincides with when the screen is powered off due to inactivity (Will soon try to disable that and some more automatics...)

It might be that the problem started after an unclean shutdown (power outage on stationary system). This thought is because my other cinnamon system (a laptop), updated to the same level, do not suffer from this problem!

So, I'm truly thankful for tips and hints about where to start looking!

/pste