/EXCEPTION_FILE=file-spec
By default, failures are only written to SYS$ERROR. Failures can
also be reported to an exception file. The name of the exception
file is given with the /EXCEPTION_FILE qualifier. The file will
only be created should a failure occur; the file will have the
protection mask (S:RWED,O:RWED,G,W). For each account whose
migration fails, an entry will be made to the exception file. The
entry takes the form of one or more lines of comments followed by
a line containing the failed username and any optional password
and destination username. The format of the exception file is
such that it can be re-used as an input file.