Exchange Server moderation not working

Messages in arbitration mailbox will not expire if the arbitration mailbox does not have a retention policy assigned

Run following command to check if arbitration mailbox have retention policy.

Get-Mailbox -Arbitration | fl displayname,retentionpolicy

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DisplayName     : Microsoft Exchange Approval Assistant
RetentionPolicy : ArbitrationMailbox
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If “Microsoft Exchange Approval Assistant” mailbox doesn’t have any retention policy assigned, you should assign ArbitrationMailbox policy to it.

In order to manually start retention policy

Start-ManagedFolderAssistant "Microsoft Exchange Approval Assistant"


In order to Check statistics for "Microsoft Exchange Approval Assistant" mailbox use the command below;


Get-Mailbox -arbitration | Get-MailboxStatistics