Question : Should you dismount exchange database before exhange updates?

After upgrading server 2008 R2 Std to 2008 R2 ent I found that it made caused my exchange database to go in to an inconsistant state which wouldn't be repaired. This server only does exchange 2010. So before installing exchange and SP upgrades for windows should I be dismounting the database first?

Answer : Should you dismount exchange database before exhange updates?

I can't find any clear guidance on this one. It does not seem to be a tested scenario.

I found this thread with other people describing similiar problems:
http://social.technet.microsoft.com/Forums/en-CA/exchangesvrdeploy/thread/fd8d20ef-b4bc-4e8e-8c3f-8c598c8016d6

From my understanding it should work, as long as you stop all exchange services prior to the upgrade.