Thanks. I'll give it a spin. I can't recreate the problem at will so
it might take a while for it to hit again.

I didn't see any old mlock processes out there and lsof didn't show any
other process having the FIFO matching the IMAP server process.

Thanks again for your Mark. What OS did you settle on after AIX
retired? I'm about to prototype a replacement Intel Linux box.

-nik