Error ORA-01172

ORA-01172: recovery of thread string stuck at block string of file string

Cause: Crash recovery or instance recovery could not apply a change to a block because it was not the next change. This can happen if the block was corrupted and then repaired during recovery.

Action: Do a RECOVER DATAFILE for the file containing the block. If this does not resolve the problem then restore the file from a backup and recover it.