Can somebody tell me what would happen in the following scenario? Day 1: server backs up at 10pm Day 2: users work throughout the day, but disk failures occur at 6pm and drive that Exchange is stored on is unrecoverable Day 3: repair server, restore from tape Under normal circumstances (and no Cached Exchange Mode), all emails from 10pm Day 1 to 6pm Day 2 would be lost (since we need to restore from tape and no transaction logs are available). BUT, what if the client is using Cached Exchange Mode?Once the server comes back online, and the client connects, what happens to all the emails that were available in the client's OST file but not on the backup tape? Thanks!

Can anyone offer any insight?

Since no one answered, i'll take a stab. I believe your assumption is correct, that you will lose the emails once outlook re-synchs, unless you could have your users export the mail as a PST, then re-import; i've never done a restore in that scenario, so its just an educated guess.

Clarify: You want to know what will happen to users current OST files if they connect to the new recovered database and resync their mailbox with it, right? Basically, Knightly has answered the question, here I just want to supply a little bit: Because DR [Disaster Recovery] will let users losing the latest data, so since outlook 2003, Cached Exchange Mode provides a function called Exchange Recovery Mode which was designed to handle this kind of situation You may get more detailed from the article Using Outlook 2003 Exchange Recovery Mode with a Dial Tone Database