1. Open the EMC goto --> Orgaination Configuration --> Mailbox --> Database Management
Right click for the mailbox click <Properties> goto the maintenance tab and un-check the <Circular Logging> function.
2. Dismount / mount your mailbox (it got around 10 minutes for a 150 GB mailbox)
3. <F5> to refresh the EMC to ensure database mount successfully and the passive copy is health (sometime <F5> cannot show the real time status workaround re-open EMC)
4. Under the EMS to vertify the status
Get-mailboxdatabase | where {$_.circularloggingEnabled –eq $true}
...or you could do this:
Set-MailboxDatabase -CircularloggingEnabled:$true















