Comment 34 for bug 432964

Long time no see answers to this problem. I have it in a newer distribution:

Linux xxx 3.0.0-14-generic #23-Ubuntu SMP Mon Nov 21 20:28:43 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

I was changing the main group of my login with "usermod -g newgroup user". Later, I did erase the old group. The operation apparently finished well. But after restarting, my login does have only the newgroup, I lost my root privileges so modifications from the session have been impossible.

I tried starting from recovery mode, and couldn't add group to my login because couldn't lock file /etc/passwd. Checking I found this bug, and could check in my system the existence of

-rw-r--r-- 1 root root 1929 2012-01-07 20:28 /etc/passwd
-rw------- 1 root root 1928 2012-01-07 20:20 /etc/passwd-
-rw-r----- 1 root shadow 1279 2012-01-07 17:48 /etc/shadow
-rw------- 1 root root 1250 2012-01-05 23:27 /etc/shadow-

I tried erasing such *- files aka passwd- and shadow-, from recovery session as root, only got message telling me the files are read only.

Any workarounds ? cheers.