I *think* (I said "think") I have found the culprit. The CMUCCVMA server was running SP4 with Rel.3 of CARD MODULE and a clobbered A-disk, which might account for the swapping of two blocks of 400 bytes (although 400 bytes is not a remarkable number for CMS-format disks -- unless the disk was formatted blksize 800, in which case it's a half-track (see QQTRK &co) and it's a *very* reasonable explanation). Marc had to reformat his server's A-disk and re-install LISTSERV from scratch, so PLEASE check your own version of CARD MODULE if you're running SP4 and you've not done it yet. Note that it will not start damaging your disk until a certain number of files have accumulated on it (there is no hash table if the disk does not contain enough files). I will ship version 1.5h out as soon as Marc has re-installed his server. Please note that LISTSERV update shipments are NOT cumulative like IBM's PUT (Probably Unexpected Troubles ;-) ) tapes, so be careful not to skip any update shipment. Do not install 1.5h unless you are already at 1.5g level! Some of you may not have received the 1.5g files or may have received them damaged (I asked those postmasters who received damaged copies to kill the files sent out by their servers when the destination link was still down). In that case please contact Harold and he'll send you a copy. Marc: you'll have to install UPD15H too since I altered two files since the shipment I sent you (cosmetic changes but I prefer to have all servers bearing the same release number with the exact same status). Eric