Workaround:
1. Ensure the Exchange Servers are running A minimum of Exchange 2010 SP3. There is a known issue that can cause unexpected database growth in Exchange: http://support.microsoft.com/kb/2621266
2. Ensure that Collaboration Services 3.7 with the latest Hoftix rollup pack for Collaboration Services has been installed on each Collaboration Services server in the Collaboration. These downloads are available on the support portal website:
https://support.quest.com/collaboration-services
3. Collect Current Whitespace and Mailbox Folder Statistics for the Mailbox Database By running the Following from the Exchange Management Shell:
Get-MailboxDatabase <DATABASE_NAME> -Status | Select Name, DatabaseSize, AvailableNewMailboxSpace > C:\Temp\DatabaseStatus.txt
Get-Mailbox -Database <DATABASE_NAME> | Get-MailboxFolderStatistics | Where {$_.FolderSize -gt 1KB} | FT Identity, ItemsInFolder, DeletedItemsInFolder, FolderSize > C:\Temp\MailboxStatus.txt
4. From the Exchange Management Shell Reduce Retention Times for The Mailbox Database And Fine Tune the Mainenance Schedule:
Get-Mailbox -Database <DATABASE_NAME> -ResultSize Unlimited | Set-Mailbox -RecoverableItemsQuota 2MB -RecoverableItemsWarningQuota 1MB -SingleItemRecoveryEnabled $false, -RetainDeletedItemsUntilBackup $false -RetainDeletedItemsFor 0.00:00:01
Set-MailboxDatabase <DATABASE_NAME> -RecoverableItemsQuota 2MB -RecoverableItemsWarningQuota 1MB -RetainDeletedItemsUntilBackup $false -DeletedItemRetention 0.00:00:01 -MailboxRetention 0.00:00:01
Set-MailboxDatabase <DATABASE_NAME> -MaintenanceSchedule {Sun.8:00 PM-Mon.7:00 AM, Mon.8:00 PM-Tue.7:00 AM, Tue.8:00 PM-Wed.7:00 AM, Wed.8:00 PM-Thu.7:00 AM, Thu.8:00 PM-Fri.7:00 AM, Fri.8:00 PM-Sat.7:00 AM, Sat.8:00 PM-Sun.7:00 AM}
5. On the Mailbox server hosting this Database restart the Information Store Service from within the Exchange Management Shell:
Stop-Service MSExchangeIS
Start-Service MSExchangeIS
6. Use the Exchange Shell to Tigger Mailbox Cleanup:
Clean-MailboxDatabase <DATABASE_NAME>
Get-Mailbox -Database <DATABASE_NAME> -ResultSize Unlimited | Start-ManagedFolderAssistant
7. Once the changes above have been made allow Exchange to run for several days, then verify from powershell that whitespace has been reclaimed by purging the deleted items from the mailboxes. This can be confirmed by running the following cmdlets and comparing the output to the information initially collected
Get-MailboxDatabase <DATABASE_NAME> -Status | Select Name, DatabaseSize, AvailableNewMailboxSpace > C:\Temp\DatabaseStatus-PostChanges.txt
Get-Mailbox -Database <DATABASE_NAME> | Get-MailboxFolderStatistics | Where {$_.FolderSize -gt 1KB} | FT Identity, ItemsInFolder, DeletedItemsInFolder, FolderSize > C:\Temp\MailboxStatus-PostChanges.txt
Note: The above Proceedure will ensure that Whitespace is properly reclaimed by Exchange and made available for Reuse. If this leaves an excessive amount of whitespace in the database, that needs to be released, please consult your Microsoft Exchange Documentation on how to perform an offline defrag of the databaes files using ESEUtil.
