I have customers that regularly have mailboxes that get randomly deleted.

The VM extension block is there but the mailbox block is gone. Their greeting still plays but it hangs up on them because they don't have a mailbox block.

Then I have to go in and readd the mailbox block and it works fine.

Seems to happen to a lot of customers.

I have one small customer on a 7100 and she says she needs to readd random people's mailboxes each week.

The admin password (all goose eggs) had been changed.

Does anyone else experience this or have any insight or thoughts on it?

I take it you've checked the applicable mmc's to make sure those extensions are set to both?

Also check the error/port activity logs to see why it was deleted

I had something similar on a 7400, turned out to be the check-in/out in hotel/motel mode deleted both the ext and mbx blocks m

Does the Both thing apply even if I have the SVMi Auto Set Up set to No?

Not sure, I always have autosetup as yes, and then adjust the mailboxes accordingly.

Auto Setup 2.1.6 was set to No.

SVMi Create Subscriber 5.9.1 was set to Both for all subscribers