Exchange Mailbox Quarantined

Sometimes an Exchange mailbox will get quarantined due to mailbox threads hanging. Reasons may be corruption, AV scanning, backups, storage issues and all manner of things.

For Exchange 2013 onwards:

Check which mailboxes are quarantined:

Get-Mailbox | Get-MailboxStatistics | Where {$_.IsQuarantined -eq $True} |  fl DisplayName

Scan for corruption:

New-MailboxRepairRequest -mailbox <logon_id_of_mailbox> -corruptiontype Aggregatecounts,searchfolder,provisionedfolder,folderview

Check Repair Progress:

Get-MailboxRepairRequest -mailbox <logon_id_of_mailbox>

Re-enable mailbox:

Disable-MailboxQuarantine <logon_id_of_mailbox>