I have upgraded Ubuntu to 12.04 and now I have a problem in logging in after locking the screen: it says the password is incorrect even though I provide the valid password. I found a temporary solution by switching users and logging in again with the same user.
I had the same issue. It is likely the ownership is wrong for
/etc/shadow (See section "gnome-screensaver authentication failure with incorrect
/etc/shadow permissions" of this page).
You need to
sudo chown root:shadow /etc/shadow then
sudo chmod u=r,g=r /etc/shadow See this bug report.
The interesting question is "Why ownership changed?". Because I don't remember changing it.
I could resolve this issue with the following permission changes:
sudo chown root:shadow /etc/gshadow sudo chown root:shadow /etc/gshadow- sudo chown root:shadow /etc/shadow sudo chown root:shadow /etc/shadow-
Found here: http://ubuntuforums.org/showthread.php?t=1006366
I am using Ubuntu 14.04 and I had the same issue
By mistake I ran a chown on the root filesystem (Yikes!) and since then I started having the issue described here.
I ran the command given in oshobov's answer, but that did not work for me, but using my own account instead of root made it work.
sudo chown your-username:shadow /etc/shadow
protected by Community♦ Dec 24 '14 at 13:57
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