After you Post Till, I doubted myself because I have manipulated the password files 2 months ago as I transferred this ISPC from Mandriva to debian and the UID:GID's differ at installation. Actually it will change depend on the sequence of installing applications.: cool:
However every time changes was made by the admin on the users and domains the group entry "users" seem to be duplicated!
On the 4th I cleaned the group files and today the server crashed again and had to re-do it.
duplicate shadow group entry
delete line 'users:*::tang..<Snipped! more than 100 account names>..raining'? y
grpck: the files have been updated
Is there an ISPC process that manage "users" group? could it be DB data errors and or corruption. The test and repair procedures in ISPC show no DB errors.