Duncan Pryde (6/28/2012)
I got led astray by the error message. Since it said there was no current database backup, I thought that meant you couldn't do a differential backup at all (since there was no full backup to "diff" against). Moral - error messages don't always say what they mean...
To follow on from this point, the message you get when performing a diff backup against a database where a full backup has not been taken is:
Msg 3035, Level 16, State 1, Line 1
Cannot perform a differential backup for database "xyz", because a current database backup does not exist. Perform a full database backup by reissuing BACKUP DATABASE, omitting the WITH DIFFERENTIAL option.
Msg 3013, Level 16, State 1, Line 1
BACKUP DATABASE is terminating abnormally.
Seems quite similar to the log backup message in the way it refers to a current database backup, but this time actually means that there is no current backup.