We have a new, month-old server with a dozen mailboxes. Out of the tens of thousands of messages stored, I get the following error for 5 of them: MBDataInputStream::PrepareLongProperty: Failure (winerr = 0x8004011b) to read long property 0x1009. File [....]: can't read, error -1012 (feature unsupported) This would have been a minor issue, but I'm trying to troubleshoot a frustratingly hypocritical Retrospect issue, and as Dantz currenly has no clue what's going on, they pointed a finger at the above error and suspect a corrupt DB. We're running an updated SBS 2008 with Exchange 2007. The store is about 7GB and is not the product of migration. Besides Retrospect, we're not experiencing any operational problems. The above error is taken from the Retrospect log. The Retrospect problem is that backups wrongly report "no items to back up" when several mailboxes are selected in a script, but will back up the items when one or few mailboxes are selected. But Retrospect isn't the topic here... 1. How do I know whether to suspect a corrupt Exchange DB? 2. I understand that running isinteg should not be taken lightly, and be run only when there's a need. Is this a relevant need? 3. What are the risks of running isinteg (in check-only mode)? Is there a risk of re-mounting problems, and why? 4. Are there any (relevant) mailbox health checks that can be run without impeding a production environment? Thanks, even if it's just for reading through :-)

Usually you get indication in event log about database corruption. However isintet in check-only mode doesn't harm anything but it is recommended to take backup to be safer side before operation. BTW, how many DBs you have? You can move all the mailboxes to new DBs and check the issue because move mailbox operation skips the corrupted or bad items and in that way you can remove the corruption. You should definitely try it and move mailboxes operation doesn't require to shutdown email service.Amit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com