Hi I have been in the process of planning our Exchange 2007 upgrade from 2003. As part of this process I have performed co-exisitng installations of exchange 2007 servers into ourDev andTest Environments. All our test and Dev Servers are Virtualised, so I am using the Exchange 2007 32bit version. The Dev Exchange 2007 box was installed several weeks ago, and was working perfectly but now I am unable to mount any mailstores (both new and exisitng ones)on the server as it returns messages similar to below: Error: Exchange is unable to mount the database that you specified. Specified database: 59eb0f14-43b9-4296-a9cc-c07d524a1464; Error Code: MapiExeceptionAmbiguousAlias: Unable to mount databse (hr=0x80004005, ec=2202). Since rebooting the Test Server after in the exchange 2007 install, it too is getting this error.The test And Dev Exchange Servers are in different forests. And none of the tools in exchange 2007 seem to be able to find any problems.. Can anyone help me to resolve this issue. Cheers Phil Woolger

I am experiencing the same issue, in a 64bit environtment. I am getting events 9519 and 9518 from MSExchangeIS when I try to mount the mailbox databases in the Application Eventlog. "Error 0x89a starting database" I have found this article for Ex2k3, but havent manage to solve it yet: http://support.microsoft.com/kb/932599

This is happening to us on a brand new install of Exchange 2007 64bit. We are attempting to upgrade from Exchange 2003 but can't get the stores mounted on 2007 to even begin to think about copying over mailboxes. We did a complete Server 2003 reinstall followed by an Exchange 2007 reinstall so the system should be as clean as you can get. We also found the articles on EX2k3 but nothing has helped so far.