There is a serious bug in CP release 5 (all SLUs <= 504) which causes CP to check only the first four characters of the userid on a match for a class D CP CHANGE command. That is, if you do a CP CHANGE LIST R ALL CLASS Z, all the files in LISTSERV's reader will be changed, as well as the files on LISTTEST and LISTING and... This happens only if the 4-characters userid does exist, which was the case at CEARN (it is our test list). If you have a list called MAIL-L or MAILBOOK, then all files in the MAILER reader would be affected, etc. This is a very dangerous bug indeed. This also explains why rejection notices got unexpectedly distributed to a list which had nothing to do with it. Sure enough, IBM did a CLC USERID,SFBUSER which I have always said is very bad programming practice. USERID being defined as DS 2F, it has a length of 4 and not 8. To fix this you must hit module DMKCSW. This is another argument for moving to OCO: with OCO you have strictly no means to solve the problem. Your system therefore gets seriously damaged, whereupon you can sue IBM and get them to give you some free program products to compensate for loss of spool files :-) Eric