The documentation lists 'keep', 'strip' and 'all' as valid values, but only 'keep' is allowed. The others give you an exit with "Illegal option: {app_file,all}". The following line in reltool_server.erl needs Val to be both 'strip' and 'all' simultaneously: app_file when Val =:= keep; Val =:= strip, Val =:= all -> In 0.5.3 (R13B04) and the dev branch.