[PLUG] Incoming mail not delivered to inbox: how to find why

[Rich Shepard]

   Another new experience: this morning my inbox had no new messages. Even
with no external senders, reports from logwatch, pflogsumm, and dirvish
backups have always been delivered. A test message from my personal domain
to my business domain also was not delivered.

   Messages from mail lists are directed to the proper file by procmail (via
recipes.rc) so it's only my alpine INBOX that's affected.

   I would appreciate ideas on quickly finding what broke so I can fix it.
I've no idea where to start.

Rich