TRUNCATEFAIL, Truncating xxxx from aaaan OpenVMS blocks to bbbb blocks failed
MUPIP Error: This indicates that a MUPIP BACKUP copied a database that extended during the copy and the attempt to return it to the proper size failed.
Action: Examine the subsequent message for more information. It maybe possible to make the copy usable by performing a MUPIP EXTEND to the actual (current) size take the GDS blocks from the extension size in the file header, and verify the same against the reported RMS blocks. You will need to rename the file since the file in this state will have a temporary file name rather than the expected name from the BACKUP.