Close to 50 GB in Outlook and considering Email Archiving? Read before you turn it on

If your Office 365 mailbox is getting close to 50 GB and you’re considering enabling archive mailbox, read on.

• When you turn on archiving, technically called “In-Place Archiving,” it creates another mailbox in the user’s Outlook with its own calendar. And the most commonly cited assistance page does not really tell you about the split unless you thoroughly read it and click on the section entitled “Instructions for end users” towards to end.
• To make matters worse, all emails and calendar items that are older than two years are automatically moved from the main mailbox into the online archive mailbox. Yes, two years is the default. There’s no alert during the enablement, either. Why they thought two years is enough as default is beyond me.
• If you realize you made a mistake, there is no revert button or a straightforward process to undo it. Pretty unbelievable.
• And even if you change the archiving duration to, say, 5 years or 7 years, it will not revert any of the changes. It applies to all calendar items and emails from the point archiving was turned on.
• Users who are used to checking their calendars and emails on their phones now have to take the extra step of looking at what is effectively another mailbox. And sometimes, the Outlook mobile app does not even show the online archive at all. (I hear the feature to show online archive was added only last year.)

So now, you have a split mailbox, with emails and calendars in two different places and no quick way of going back. But you can go back. The following is a somewhat manual process, but it will work.

The failsafe but manual process:

Set the archiving duration to, say, 15 years, enough so that no email or calendar item will be archived. Export all items in the online archive as a PST for safekeeping/backup. For calendar, open two instances of Outlook Calendar. In one, open the online archive calendar. In the other, open the main calendar. Select no more than 150 items at a time from the online archive calendar, then drag and drop them into the main calendar. Repeat this in batches. This process moves the calendar items. If you do not have a large number of emails, you can drag and drop them from the online archive to the main email account until the archive is empty. Then go and turn off archiving. The archive mailbox will disappear within an hour.

The quicker option (but I’ve not tested it):

The export of the entire online archive as a PST and its import into the main mailbox should work. Untested. If you have for large PSTs, it would be great to know that it works!

Wish

Hopefully MS creates a revert button that can be used at least within the first 24 hours and saves the users from the pain. And that it alerts/asks for the number of years to set the archival duration to be during enablement.

😩