When dealing with deleted items in Office 365, it’s important to remember that there are always 2 retention policies that are applied to items that are deleted:
- The first retention policy is the one that can be edited in the Exchange admin Center (detailed below), and affects items that are sent to the Trash, or Deleted Items folder – default retention is 30 days. If a user used Shift-Delete to delete an email, it bypasses the Trash altogether, and goes into the Recoverable Items folder.
- The Recoverable Items Folder holds on to items deleted from the Trash, or by a user Shift-Deleting them by default for 14 days. This retention period can only be edited using PowerShell.
If you need to change the retention period on Deleted Items (the first one), you do so by editing the retention tags applied to the mailbox.
Start by logging in to the Exchange Admin Center, click on compliance management and then retention tags:
You can see here that the default retention period on Deleted Items is 30 days – go ahead and double click on the Deleted Items policy to edit it:
Change your retention period to the number of days you want deleted items to be kept for, or Never to set the retention to unlimited.
Once you click Save, you can see that the retention tag has changed from “Delete in 30 days” to “Unlimited”. You can just as easily make this 1 year, 2 years, or whatever you want it to be, depending on your business requirements.
Now if you go back to the retention policies tab, you can see that the default MRM policy has now been updated to never delete deleted items.
If necessary, you can create a new MRM policy with whatever settings you need, and assign them to individual users, or you can create new retention tags that users can pick from to manage their own retention on specific folders. A good example of this would be an archive folder where a user wants to only keep emails for a year, and then have them purged automatically after that.
The controls are quite granular, and you can make the policies and tags do pretty much whatever you want… have fun!