How to clear the Discovery Holds folder

To find whether this discovery holds folder is completely full, use the below-mentioned command. 

Step 1: Connect-ExchangeOnline

and then,

Step 2: Get-MailboxFolderStatistics -Identity user | select name,foldersize

Note: This DiscoveryHolds folder is having a limit of 100 GB. If it is full, we will get issues like "Unable to clear deleted items folder", "deleted items are getting auto-restored" etc.,

One of the reasons for this folder is full: If Organization Hold is turned on(All Exchange mailboxes are selected in Compliance Retention Policy) or the Individual ID is selected on Compliance Retention Policy. 

Solution: 

Please try the below-mentioned steps to overcome this issue. 

Step 1: Exclude the DiscoveryHolds full ID in the Compliance Retention policy or run the below-mentioned commands in PowerShell. 

Connect-IPPSSession

and then,

Set-RetentionCompliancePolicy -Identity "Compliance Retention Policy Name" -AddExchangeLocationException user

for multiple users, 

Set-RetentionCompliancePolicy -Identity "Compliance Retention Policy Name" -AddExchangeLocationException user1, user2, user3

Now on PowerShell, 

Connect-ExchangeOnline

and then, 

Set-Mailbox -Identity user -RetainDeletedItemsFor 0

and then run the below-mentioned command two times. 

Start-Managedfolderassistant -Identity user

Start-Managedfolderassistant -Identity user

After 2-3 minutes, run the below-mentioned commands. 

Get-Mailbox "user" | FL DelayHoldApplied,DelayReleaseHoldApplied

If the output is received as true for any above-mentioned holds, then run the below-mentioned commands. 

Set-Mailbox user -RemoveDelayHoldApplied
Set-Mailbox user -RemoveDelayReleaseHoldApplied

and then run the below-mentioned command two times. 

Start-Managedfolderassistant -Identity user

Start-Managedfolderassistant -Identity user

After 2-3 minutes, this DiscoveryHolds folder will become zero as per the below-mentioned screenshot. 

This process helped me a lot. If you have any doubts/concerns/suggestions about this post, please comment below. 

Best Regards,

Venkat Kiran Kona.