| ERROR | datafile string has been restored from an RMAN backup with undo block compression. |
| CAUSE | Flashback Database could not flash back the database because a file was restored from an RMAN backup with undo block compression, and the Flashback target was to a time when the missing undo may be needed to open the database. |
| ACTION | Restore an earlier backup of the file and retry the command or Flashback to a later time. |