I have encountered a strange issue with my Ubuntu 15.10 install: Usually, I lock my desktop with Ctrl+Alt+L when I leave my computer, and when I come back, I enter my password and can continue working.
In the last few months, I have encountered a problem three times: The lock screen kept telling me my password was wrong even though it wasn't. I checked caps lock, I tried another keyboard. I opened a shell with Ctrl+Alt+F1, logged in with that exact account. Worked. Used
passwd to change password to something simple like '123'. Went back to the lock screen with Ctrl+Alt+F7, tried '123', still "wrong password".
I had to restart my computer, lost unsaved documents (luckily not that much work because I usually save everything before locking the screen), and re-open all of my programs.
Any idea why? Why does the lock screen keep telling me my password is wrong when it obviously is correct?
Here are the relevant lines from
Jun 26 20:58:45 my-device-name lightdm: pam_unix(lightdm:auth): authentication failure; logname= uid=0 euid=0 tty=:0 ruser= rhost= user=myusername
Jun 26 20:58:48 my-device-name lightdm: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Jun 26 20:58:48 my-device-name lightdm: PAM adding faulty module: pam_kwallet.so
Jun 26 20:58:48 my-device-name lightdm: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
Jun 26 20:58:48 my-device-name lightdm: PAM adding faulty module: pam_kwallet5.so
Jun 26 20:58:48 my-device-name lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "myusername"