What’s new on the fly: Server Roles: Microsoft Exchange Server 2013 Preview consists of the following two server roles Client Access server role and Mailbox server role Exchange2013 Server Roles Exchange Administration Center...

I have started seeing this issue recently while doing my usual customer visits , kindly check the workaround for the time being http://blogs.technet.com/b/exchange/archive/2012/06/28/mailboxes-on-a-database-are-quarantined-in-an-environment-with-system...

documentation http://technet.microsoft.com/en-us/library/bb124558(EXCHG.150).aspx