Office 365 mailbox is not backed up

If your small or midsize business uses Office 365, there is probably no backup of your mailboxes. A backup – long-term retention of a copy of your mailbox in a separate place – requires a third-party service at startling expense.

It’s starting to be a problem that needs to be solved. Prepare yourself for another monthly bill.


Backups of Office 365 mailboxes are just as important, and should be considered as much of an essential requirement, as backups of an onsite server. You can recover deleted items from Office 365 mailboxes for a limited time, but Microsoft does not otherwise provide any native option to back up Office 365 mailboxes. A third-party backup service is required if you want to recover mail, contacts or calendar entries from an Office 365 mailbox. A long-term backup might be invaluable protection in the event of a malware attack, or in the aftermath of the departure of a malicious employee, or if items are accidentally deleted and no one notices for longer than Microsoft’s retention period.

  • IT providers need to choose a backup provider and encourage clients to sign up for Office 365 backups.
  • Small and midsize businesses need to recognize the importance of backups and be prepared to add yet another expense to their monthly bottom line.

As with OneDrive, Microsoft keeps your Office 365 mailbox safe. If you accidentally delete a folder full of mail or a contact or appointment, you can recover it from the Deleted Items folder. Once something has been removed from Deleted Items, it can be recovered for an additional 14 days from a lightly-hidden folder of “recoverable items.” (In Outlook, click on Folder and look for Recover Deleted Items.)

There are three circumstances where you might want a long-term backup of Office 365 mailboxes.

  • Unintentional deletion of data that is not noticed at the time – a finger slips, or you make a mistake when you’re decluttering Outlook.
  • Malware or viruses destroy data in mailboxes, or hackers get into a mailbox and delete data.
  • Intentional deletion of data by employees seeking to cover their tracks or cause harm on their way out the door.
Office 365 - Microsoft terms of service recommend third party backups

Microsoft has various Office 365 options for retention and archiving, but none of them are substitutes for a true backup. Microsoft admits it does not have any ability to restore a mailbox to a particular point in time and explicitly recommends third-party backups.

Theoretically, an Outlook mailbox can be backed up by exporting to a .PST file. In reality, that is never a good answer. There is no way to automate the process; .PST files are fragile; the export is agonizingly slow; the files are large and difficult to store; and searches in .PST files are arduous and prone to error.

As a result, backup vendors are stepping up with Office 365 backup programs. The first customers are enterprises with in-house IT employees who are taking on the administrative burden of handling the Office 365 backups. In my experience, almost no small or midsize business is doing backups yet, and IT providers are just now starting to realize that they should be offering Office 365 backup services to small and midsize clients.

As you might expect, the choices are hideously complicated. Many of the backup services are only sold to IT providers, not directly to Office 365 clients. Some of them do not cover public folders or shared mailboxes. Some (but not all) include files in OneDrive for Business, Sharepoint libraries, and data in Microsoft Teams. Most of them do not have direct access by the end-users to restore items; only the IT provider or administrator can recover data.

How much does it cost? It’s all over the map. If you want a ballpark number, figure on $6-$8/month per mailbox. Your brain will hurt if you try to compare the apples and oranges. Some prices are the same regardless of the number of mailboxes; others vary or have a minimum. Some prices include unlimited storage; others set an artificially low storage limit and charge extra for more space. Some prices vary depending on whether you provide your own storage in AWS or Azure, or use the vendor’s storage. If you see something that appears to be a deal, you’re probably missing a detail or two.

In other words, the backups are almost as expensive as the mailboxes themselves. It is exactly as frustrating as paying the monthly fee to back up your server, or paying the bill for homeowner’s insurance, because it’s expensive and the best case is that you never need to rely on it.

Here’s a partial list of Office 365 backup providers. If you’re in a small or midsize business, visiting these sites will make for fascinating reading, but you will likely not purchase this coverage directly. Reach out to your IT provider and tell them you’re anxious to pay even more money for support. They’ll have to evaluate the options, choose a service, come up to speed on its quirks, and offer it to you.

Bruceb Consulting clients: Don’t call me, I’ll call you. I’m evaluating a few of these services now. I’ll let you know when I’ve got something for you to test.

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