I have a computer that has Outlook 2010 installed on it (and it uses a hosted Exchange provider). However, there were some possible issues with the OST file on that machine (it was causing duplicate contacts and the one that Outlook/Exchange determined was the most recent wasn't always the actual most recent one) and so Outlook hasn't been run on it for a few months now (the same mailbox is being accessed from two other copies of Outlook - v2007 and v2013, and also from OWA and via mobile device ActiveSync).

The other day, I wanted to actually see something in an older copy of the mailbox (I was concerned that a calendar sync tool might have made some drastic changes to the Exchange mailbox), so I took the computer offline by disabling the wired and wireless network adapters and then launched Outlook. Weirdly enough, it showed that it had most recently been updated only a few hours before, even though the most recent mail was from several months ago. And then, all of a sudden, it started updating the most recent mail and slowly bringing in newer mail. I am almost positive Outlook was reporting that the mailbox was offline/disconnected, and I confirmed there was no network connectivity, and yet what started off as having the most recent mail from a few months ago started to slowly change to more and more recent mail. Also, weirdly enough, the Outlook reminders pane never popped open despite me closing and restarting Outlook twice. I finally decided not to let it finish, and just closed it, but anyone have any ideas how this could happen?

And as far as I know, on this particular computer, there aren't any applications that access the OST mailbox independently (i.e. sync tools, etc.) - although it's possible I am wrong. If there were though, I would expect them to run Outlook in the background when necessary, but in doing so Outlook would actually be running and connected and therefore when I actually launched it this time around, it would have been nearly up-to-date instead of this weird, slow update that seemed to be occurring somehow while the computer was offline.

Any ideas? Thanks!