> This is really an indictment of M$

No, it really isn't. For two decades all across the world people have kept Outlook running well enough to function in all sorts of scenarios, including those more difficult than a military ship at sea.

It's not like Thunderbird and Alpine are magically immune to having corrupted data stores and invalid configurations. This is entirely due to lack of proper maintenance.

There are phone switches that were made in 1982 that are still running phone service, including 911 calling, for mid-sized towns.

And yes, postfix or Exim or qmail, once set up, in a fixed configuration like boat only email, could easily run for decades automatically.

Poor choice perhaps, given how many security holes there were in Sendmail.

I have a sneaking suspicion that the failure was something generic like running out of disk space, which nobody had both the authority and time to fix.

There are many things that could have gone wrong. Maybe they ran out of disk space. Maybe some critical certs expired.

I was wondering if the previous power issues mentioned had borked the exchange database. Still, thats a day or two to fix, not weeks.

Those are issues that would arise within a couple of years, not over 20 years later. If the ship doesn't have anyone qualified to administer computers, then archiving etc. would have to be automated. If the ship used to have such personnel and no longer does, that is certainly a problem at a higher level than the captain.