Message Oracle ORA-38705 - Expected block size string does not match string in log header.

ERRORExpected block size string does not match string in log header.
CAUSEWhen the flashback log file header was read, the block size in the control file did not match the block size contained in the header.
ACTIONIf you are doing a FLASHBACK DATABASE, then the flashback cannot be performed because of the corrupted log. A restore and an incomplete recovery must be performed instead.