Microsoft has simplified the process of removing a mailbox from quarantine starting with Exchange 2013. (Before it was a more complicated process, involving registry edits).
Keep in mind that Exchange quarantines mailboxes for a reson. It tries to correct a problem automatically, but if it fails, it will quarantine the mailbox again, so the root cause of the problem needs to be identified.
First, you need to find which mailbox was quarantined. Open Exchange management shell and run the follow codelet:
Q. I would like to copy some data from a shadow copy image, is there any way that I can access it as a drive or directory (mapped or mounted)?
A. Yes, this can be achieved in the following steps:
Open command prompt and run:
vssadmin list shadows
This will produce the following output:
Q: We have switching our Exchange server to another one, but the autodiscover keeps reverting back. Is there a way to fix this?
A: You can manually bypass the Microsoft Exchange settings. (Below was tested on Exchange 2010 and 2013.)
Adjust the following registry settings. Depending on your version of Microsoft Office the number between "Office" and "Outlook" will change. For example, in Outlook 2007 it is 12.0, for Outlook 2010 it is 14.0, for Outlook 2016 it is 16.0: