Outlook 365
Deleting old email by date
This article applies to the Windows online version of Outlook. This may not apply to the Outlook desktop app for Windows or Macintosh.
In the old days, a global policy that automatically deleted emails in your Deleted Items folder that were over several months old no longer applies, so now, deleted items are saved forever. This can be bad for several reasons. First, if your mailbox size gets too large, your email will get slower and slower to access, but worse, if you start exceeding your storage limit, you will no longer be able to receive email, and accessing your mail in general will become problematic.
To manually clean up old emails, log on to your Outlook.offfice.com account. Click the gear to get to your Settings. Click the link at the bottom to view all Outlook settings. Then click General, then Storage to get here:
Your folder list will appear. Each of them has a pop-up to delete old messages. For example, to delete messages from your Deleted Items that are older than 12 months, pop up the trash can icon and select 12 months and older, as shown here.
WARNING: This deletes mail by actual message date, not by the date that you deleted the messages. Use this at your own risk. To sort by date deleted to assist in deleting the oldest deleted messages, see this article.