Managing the quota (mailbox size) of your (Microsoft 365) account using Outlook for macOS


“***NOTE*** If you have the “New Outlook” feature enabled for Mac, please use the steps associated with OWA to manage the mailbox size.”


Your Exchange mailbox has a finite storage quota (100 GB for faculty and staff). It's good practice to monitor your quota and delete unnecessary email messages to keep your mailbox well below quota.


1. Control-click your Northwestern mailbox and click Properties...


2. Click Storage to see your overall usage, as well as the amount of space each folder is using. Click OK when you're done.

3. In the main Outlook window, Control-click Junk E-mail, then click Empty Folder.

4. Do the same with the Deleted Items.

5. Above the inbox column, click on the By: menu and select Size in the drop down menu. In the same drop down menu, make sure it is organize with Largest on top. Delete emails as necessary.

6. Repeat this step except organizing by Date Received.


You can also create an auto-archive rule that will automatically save and remove email messages for you.

  1. Open Outlook > Preferences...
  2. Click General and uncheck the box named Hide On My Computer folders.
  3. Close the Preferences window and go back to your main Outlook window.
  4. In the left hand menu, create a new folder by right-clicking On My Computer. Name the new folder.
  5. Open ToolsRules.
  6. In the Rules window, under Server Rules, select your Northwestern email account.
  7. Click the plus (+) button to add a new rule.
  8. Name the rule.
  9. Edit the first criterion to Date Received and Is Greater Than and enter an appropriate time frame after it.
  10. Edit the second criterion to Move Message and move the message to the folder you created earlier. Click OK when you're done entering criteria.
  11. To activate this rule on your current mailbox, go to Message > Rules and select the rule you have created.






Article ID: 1582
Thu 5/12/22 1:39 PM
Wed 9/20/23 12:24 PM