ORA-01233: file [string] is read only - cannot recover using backup control file
Cause: An attempt to do media recovery using a backup control file found that one of the files is marked read only. Read only files do not normally need to be recovered, but recovery with a backup control file must recover all online files.
Action: If the file really is read only, take it offline before the recovery, and bring the read only tablespace online after the database is open. If the file does need recovery use a control file from the time the file was read-write. If the correct control file is not available, use CREATE CONTROLFILE to make one.