Thank you to everybody who responded both on and off the list. The problem is correctly solved and here is what happened.
This is a good example of how long an incomplete configuration can work perfectly until 0 Day when the right set of circumstances make it glaringly obvious that something is terribly wrong. Particulars follow. It all started 4 years ago when I retired after 25 years in IT and I am embarrassed to say that I was supposed to have known something about unix. In the environment where I worked, .mh_profile didn't need a line like: Local-Mailbox: "Martin McCormick" <marti...@suddenlink.net> because any system we were using had a FQDN on the okstate.edu network. I still wanted to use nmh from home with our ISP, a cable TV provider which meant a somewhat different setup in that our home network is the typical private number-space situation with a meaningless reverse DNS lookup reference and a mail smarthost that must make internet email work for each subscriber and it does so once one's own system authenticates with the pop3 server which is the reason for the local-mailbox declaration. After getting that setup, it has worked perfectly but only because I also used procmail which did the job of catching any message that landed in /var/mail/martin before it hit the ground so to speak. Recently, I had to do some work on the system that handles mail and procmail was temporarily indisposed due to the normal home directory being absent. nmh could still run but one needed to use inc to grab the accumulating messages from the mail spool. I also had put nmh on a Raspberry Pi plus other aging PC's that run Linux but don't send mail in to the network. none of them would do inc either. The proper fix was to remove the local-mailbox declaration I had unwittingly copied from the system that does send internet mail to the ones that don't and on the one that does, I now set the $MAILDROP environment variable and, so far, all is peace and bliss now. Putting a MailDrop: .mail line in .mh_profile did not change the wrong lookup but, according to the man pages for mh-tailor.conf and mts.conf, the environment variable MAILDROP supersedes .mh_profile settings and that is what happened. Hints: the strace program is your true and dear friend. You don't even need unincorporated mail for testing. Just strace -e trace=file -o output inc will tell you when it is good. Bad looks like stat64("/var/mail/martin.m", 0xbfabfd70) = -1 ENOENT (No such file or directory) Good looks like stat64("/var/mail/martin", {st_mode=S_IFREG|0660, st_size=0, ...}) = 0 You can see that there was nothing there but it is referencing the correct mail file. Again thanks, everybody. Martin McCormick WB5AGZ -- nmh-workers https://lists.nongnu.org/mailman/listinfo/nmh-workers