Oracle Error Message
ORA-19816: WARNING: Files may exist in string that are not known to database.
Reason for the Error
One of the following events caused this:
1. A database crash happened during file creation.
2. A backup control file was restored.
3. The control file was re-created.
4. DB_RECOVERY_FILE_DEST has previously been enabled and then disabled.
Solution
Use RMAN command CATALOG RECOVERY AREA to re-catalog any such files. If the file header is corrupted, then delete those files using an OS utility. Do not use messages 19817; it is used for simulating lock failure Do not use messages 19818; it is used for space reclamation before backup Do not use messages 19819; it is used to disable clearing file name