Things I found out the hard way number 25423: If you have done an imapsync from a compatible IMAP service to a brand spanking new Exchange 2010 install and the Received dates are being set to the import date – Simply ensure you have updated Exchange to the most recent Service Pack and Update Rollup and run the *imapsync *again. Then you should find all your dates are correct.

So the story goes:

I recently migrated my Exchange 2007 box to Exchange 2010 on a new, totally separate server. Normally the migration path is to install the Exchange 2010 server into the same environment and create a move request… However I have one main mailbox and a few other tiny ones on there so I thought “Screw that, I’ll just use imapsync from a Linux box”.

It all worked nicely, except the “Received” date on the new 2010 install was being set to the date/time of migration, not the original date/time (Even though the header was correct). Both the –syncinternaldates and –idatefromheader options had now affect. I ended up using a different, really inefficient method to transfer the mail. It was at this stage I realised I hadn’t bothered to check for updates to Exchange 2010.

Upon checking I had to update to SP2 and Update Rollup 5… No problems, all went smoothly and things working nicely. A few days later however, I decided to crack the imapsync problem so if anyone else had the same stupid idea I could help out. Upon the first test I realised that the problem was no longer a problem… One of the updates had seemingly fixed the issue. I went through all the release notes and have been unable to find which exact update fixed the problem, but it was obviously a bug in Exchange and not in imapsync as I first thought.