HELP E-mail accounts missing on many accounts

[jeroman8]

Just today - a lot of accounts do not have any e-mail accounts any more.
The mail folders and alias is there but not the accounts !!!

So far I cheked 12 accounts on server where 10 of them all miss their e-mail accounts.

Is the accounts listed somewhere in a file taht has been corrupt ?
I know there valias but is there a file for the "real account (pop3/imap) also ?

The space - quota on server and account is ok.
cPanel has not been upgraded.
I run manually updates only.

Please HELP!