Networks

Here's a new twist on an old problem: Rather than my whole inbox or a block of messages vanishing, one (and only one) message disappeared from my inbox, and my (only) reply to that message also disappeared. Both the received message and the reply were received/sent today. About 15 minutes elapsed between between the time I sent the reply, and the time I discovered the disappearance of both messages.

If it were anyone else in my office presenting this issue, I'd assume some sort of user error, and of course I can't completely rule that out for myself. But I'm 99.9999% certain I didn't accidentally do something to make the messages disappear. That said:
* Yes, I looked in Deleted Items, and searched all folders to see if they'd somehow been moved. Nada.
* No, I didn't close Outlook between the time I received and sent those messages, and the time that I discovered they were missing. So they couldn't have been accidentally sent to Deleted Items, and then permanently deleted when I closed Outlook (which is a preference I have enabled).
* No, I didn't change the view or apply filters or create new rules or anything else of that sort that might have hidden or moved the messages. Still, I did check filters, views and rules to see if anything was amiss. Nope, everything looks normal.
* In case it's not obvious from my first paragraph, the only strange behavior has to do with those two messages. Everything else is situation normal, including sending/receiving from the same email account that those two messages disappeared from.

A little more about my setup: Most of my email accounts are saved to a local .ost file, linked to our office's on-site Exchange 2007 server. The messages that disappeared belonged to one of those .ost-associated email accounts. I have a few rules set up on my local Outlook profile to automatically move messages to subfolders, but nothing in those rules that should have caused those two messages to disappear.

More: I just logged on to Outlook Web Access, and lo and behold, there's the (missing from Outlook 2010) message in my OWA inbox. And even after doing several send & receive all cycles from Outlook, and refreshing the browser in the OWA session - the message which disappeared from my local machine's Outlook 2010 inbox, is still present in OWA. However, the reply I sent to that message is missing from both Outlook 2010 and OWA. I did verify by phone that the person who sent me the message received my reply.

I am stumped. Any of you geniuses have any ideas or advice? Thanks!