In this Tutorial we are going over the process to identify and remove a mailbox from the quarantine, in Exchange Server 2010 a mailbox can be quarantined after 3 failures and it stays in that state for 6 hours. A cmdlet to add and remove a mailbox from Quarantine was introduced in Exchange Server 2013 but it is not available on Exchange Server 2010 and the manual process is described here.
The first step is to identify the issue on the end-user, in the following picture (although is a 2013 but the issue is similar to 2010 owa).
A simple way to test is running the following cmdlet, and in the error line we can check the nature of the issue, in our case we can see that is MapiExceptionMailboxQuarantined as depicted in the figure below.
Test-MAPIConnectivity <mailbox> | fl
Now that we are aware of the issue, our next step is to identify the Mailbox GUID and Database for the affected user, using the following cmdlet:
Get-MailboxStatistics <username> | ft DisplayName,Database,MailboxGUID –AutoSize
The second piece of information is the GUID of the mailbox database using the following cmdlet:
Get-MailboxDatabase <MailboxDatabase> | ft Name,Guid –AutoSize
Having all that information in place, we can open the registry editor and navigate to the following location.
Inside of the Mailbox (which is identified by the Mailbox Database guid), and then expand the QuarantinedMailboxes and we are going to have an entry for the affected mailbox which we can identify by the mailbox guid. In order to remove a mailbox from quarantine, remove the entry from there, and wait a few minutes to see if that works.
If you want to force the refresh, then the Exchange Information Store can be restarted.