Mailbox Dumpster (aka TotalDeletedItemSize aka RecoverableItems) hit the 100GB size quota due to a bloated recurring meeting

Scenario: You have a mailbox that is similar to the following scenario:

-On a Hold: A mailbox is protected by a hold such as a Litigation Hold, eDiscovery/In-Place Hold, SCC Compliance Hold, etc.

-Hit the Quota: The mailbox has either already hit, or is approaching, the mailbox dumpster 100GB quota

-Item Count to Size Ratio doesnt make sense, at first: When you run the following command you notice that there are very few items in the folder that is at or near the quota — it would seem that the item count and folder size doesn’t make sense for 200 items to equal 99GB. Command: get-mailboxfolderstatistics <name> -folderscope recoverable | Select Name, ItemsInFolder, FolderSize

-Symptoms experienced by the user: Users have a issue deleting email items OR may experience issues with calendaring events.

Investigation: We discovered that there is a long-lasting recurring meeting that the impacted user/mailbox was an attendee for. The organizer of the meeting would edit single occurrences of the meeting series to post meeting agendas and attachments (this is where the size bloat comes from). It appears there is a conflict with this user being on a hold, and retaining a collective buildup of all edited occurrences of the meeting series. There was around 200 individual meeting ocurrences of thise meeting series, and each item is now ballooned in size to just under 200MB each. This contributes to the size of the dumpster folder, and the overall dumpster quota.

Solution: There is a command that we can run that will cleanup all the duplicate calendar items in the dumpster, even when a mailbox is on a Hold:

start-managedfolderassistant <name> -holdcleanup.

However, in our scenario the email items lived in the Purges recoverable items folder and the command did not work in that folder. Using MFCMapi we had to do a Move (in MFCMapi language a Copy –> Paste with the move option selected) and put all those items into the Versions folder. When the messages were moved into the Versions folder, the command worked and within the hour all the duplicate messages that were ballooned in size were now gone AND the dumpster was well under quota.