Oracle Error NID-00139: Mismatched dbname for datafile string, expected string, found string

Oracle Error Message

NID-00139: Mismatched dbname for datafile string, expected string, found string

Reason for the Error

The dbname of the datafile does not match the ‘old’ dbname or the ‘new’ dbname.

Solution

Verify that this datafile belongs to the database. You may need to restore a backup of the datafile.