No M: Drive in Exchange 2003?

So you've upgraded to Exchange 2003, and now you notice that the ExIFS drive, drive M:, is no longer available. That's good! It's also normal, since Microsoft has hidden drive M: by default in Exchange 2003. There were enough cases of corrupt databases after the misuse of drive M: that Microsoft decided to take this action.

If you want to re-enable drive M:, first ask yourself if you really need to. Then ensure that you understand the ramifications of virus scanning this drive, or backing it up, by reading the Microsoft KB article here.

If you then finally convince yourself you still need drive M:, then here's how to re-enable it in Exchange 2003. You need to add a string value called DriveLetter, with a value of M, into the following location:


Obviously, the value M means that drive M: will be used. You can change this to be a different value if you desire.

If you do re-enable the ExIFS drive letter, be careful out there!

Account Deleted on September 15, 2003 at 02:38 AM in Useful Info
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Hey, thanks for this. Solved my problem immediately.

Posted by: Chris Gill at Nov 19, 2003 10:33:23 AM

Dear Sir, Can u please tell me how can I take backup of
mails from exchange 2003. My all clients uses OWA.


Posted by: Nimesh at Nov 24, 2003 10:22:23 PM

Hi Nimesh...

I would suggest that you start by visiting the 'Exchange Server 2003 Backup Resource Center' at......;[ln];exc2003backup&product=exch2003

Posted by: Chris Meirick at Nov 25, 2003 3:00:18 PM

Dear Sir, I had backup Exchange 2000 M: drive by mistake,
the outlook client can't access their emails, it's there
any way that I can recover this? Thanks.

Posted by: Pang at Jun 4, 2004 10:02:44 AM