I had updated the password on one email account on one domain out of 15 domains. All of a sudden, i began getting errors with sudo and root - saying uid 0 , and uid 1000 did not exist. I looked in /etc/passwd and only accounts for web2_ (the domain i updated) were visible!! .. root, the main accounts , logger accounts were all gone - only web2_ accounts remained. I had to login to another system and copy the first section of /etc/passwd to get the system running at half-capacity again. I'm stil getting this error. sudo: pam_authenticate: Authentication service cannot retrieve authentication info. And, I need to find out how to get ispconfig to rewrite the passwd file from the other 15 domains besides web2, i don't know all those uid's!