| ERROR | Mining could not start | 
| CAUSE | Mining could not start for the following reasons. 1. A logminer session was processing 2. The database was not mounted or not opened for read and write 3. Minimum supplemental logging was not enabled 4. Archiving was not enabled | 
| ACTION | Fix the mentioned problems and try again. Note that if you enable supplemental logging now, you will not be able to remove a transaction that has committed without supplemental logging. |