Adjusting Exchange Online Deleted Item Retention

Have you been getting frantic calls and emails from your Exchange Online users who are trying to get an email that they accidentally deleted a few weeks ago, but they can’t find it anywhere? They’re probably running up against the default limit that Exchange Online uses for deleted item recovery.

• Related: Manage Remote PowerShell Access to Exchange Online

By default, items that have been deleted in Exchange Online are available to be recovered for a period of 14 days. If you have users looking to recover items that have been deleted more than two weeks ago, then you’ll need to adjust some deleted item retention settings.

How to adjust Exchange Online deleted item retention rules

If your users need more time to recover those deleted emails, then you can increase this period up to a maximum of 30 days in just a few simple steps using Windows PowerShell. Here are the steps below:

1. Connect to Exchange Online using PowerShell. If you need to review how to do this, check out my article that walks you through how to connect to Exchange Online using PowerShell.
2. Enter and run this PowerShell command:

   ​ Get-Mailbox | Set-Mailbox -SingleItemRecoveryEnabled $True -RetainDeletedItemsFor 30

   Note: you can adjust this command to be directed at specific mailboxes or you can keep it open for all mailboxes.

3. As always, make sure to disconnect your session when you are done using one of the following commands:

   ​ Remove-PSSession
   Disconnect-PSSession

Taking a step back for a moment, let’s consider the misconception folks have with regard to Office 365 and Exchange Online. Microsoft offers 99.9% availability, but that focus is on the availability of existing data. There is no backup and recovery solution that allows you to reach back in time for data.

With an archive solution you would not be able to recover something deleted beyond the deleted item retention time. And as you’ve just learned, that time period is limited to 30 days at most. As a result, that puts you in an awkward position to provide message retrieval for those (hopefully few) moments when you need to.

Exchange Online deleted message retrieval options

What are some additional options when it comes to providing message retrieval for Exchange Online users? You have two options in this regard.

1. Put mailboxes on legal hold

The first is to place mailboxes on legal hold — also known as a litigation hold — which will retain all mailbox contents for the duration of the hold.  To be prepared continually you would need to initiate legal hold at the outset of using Exchange Online so that mailboxes are on hold and data is preserved.

This does not mean, by initiating legal hold, that end users will now be able to retrieve their own message in much the same way they can retrieve deleted items still held under the retention time. Rather, it will require an administrator to recover the items through a discovery search. It’s not an elegant solution and may require additional fees to purchase the archive piece of Office 365.

2. Use a third-party email message archiving service

The second option is to utilize a third-party, cloud-based archive solution so that messages are retained in this way. End users might be given the ability to retrieve their own archived messages in this case but they would not be capable of deleting them.

Ultimately there are options. Unfortunately, at this time, increasing deleted item retention time is a limited solution at best, with legal hold being a poor secondary option.