On Sat, May 20, 2023 at 12:53:15PM -0400, Hendrik Boom wrote:

> I had not seen these subtle discrepancies before. I am a bit
> surprised at needing permissions on the directory whe I already
> have read/write permissions on the file, which I own...

That's because of the lock files. mutt needs to create a new file in
that directory while it is modifying the mailbox. That prevents
(temporarily) the mail daemon from delivering there until it is
unlocked again, because such a simultaneous modification would result
in corrupting the file.

Not needing the locks is one of the advantages of mailbox storage
options with a separate file for each message, such as maildirs.
That's not to say that there are no disadvantages.

Even with a single mailbox file (and with locks), it is possible
to avoid permission troubles by putting the mailbox somewhere in
your home directory, owned by you and your group. Of course all
the pieces need to support that and need be told about it.

--
Ian