Email Storage Management


With Microsoft 365, you have 25 GB of email storage. However, it is still important to adhere to the UM System Email Management policy. Below are some tips for managing your email storage by keeping the files you want, filing data appropriately, and deleting the email you don’t need.

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What are the different email quotas?

  • Your mailbox has a total size limit of 25 GB. After which you will be prohibited from sending and receiving email.
  • Individual messages have a limit of 35 MB. This includes the message and any attachments. Messages over 35MB will not be sent. NOTE: External recipients may have smaller limits that may prevent delivery.
  • Coming soon: In the future, messages in Inbox and Sent folders will have retention policies of 5 years. Messages in Deleted will have a retention policy of 30 days. After which they will be automatically deleted. Email that needs to be retained longer than the folders retention policy should be moved to a subfolder to avoid deletion. More information can be found on the Electronic Mail Use and Management Procedure page.

How can I check my email quota usage?

Outlook on the web

  1. Log into outlook for the web
  2. Click the settings cog in the upper right corner
  3. Click view all Outlook Settings
  4. Click General in the left column.
  5. Click Storage
    Outlook Quota
Outlook for Windows
  1. Open Outlook
  2. Click File
  3. Your mailbox usage will be listed under Mailbox Settings
    Outlook Quota
Outlook for Mac
  1. Open Outlook
  2. Right-click on the account name within your mail folder listing and select Properties from the sub-menu.
  3. Click Storage from within "Folder Properties" screen.
    Outlook Quota
  4. Depending on the number of objects (mail folders, calendar items, contacts, and tasks) you have in your account, it can take minutes for this information to be retrieved

How can I clean up space in my email?

Outlook's Mailbox Cleanup tool is a one-stop tool for lightening your mailbox and freeing up storage space.

  1. In Outlook, choose File> Tools > Mailbox Cleanup
  2. From here you can perform any of the following
    • View the total size of your mailbox and of individual folders within it.
    • Find items older than a certain date or larger than a certain size.
    • Archive items by using AutoArchive.
    • View the size of your Deleted Items folder and empty your Deleted Items folder.
    • View the size of your Conflicts folder and delete this folder.
While Outlook for Mac does not have the same mailbox cleanup tools that the Windows version does, you can still use advanced Search and Folder Properties options listed above to identify folders that may be using large amounts of storage.

Please contact the Technology Support Center if you need additional assistance in saving space.

How can I keep the email I need?

Email that are in subfolders or folders other than Inbox, Deleted Items, and Sent, are not subject to the retention policy and will not be deleted automatically in the future. Messages should be saved only if they are records. Examples of non-record emails are:

  1. Resources material – material that has been created or received for reference purposes
  2. General routine department business correspondence – messages that have short-term administrative or operation value used to provide information or for the completion of a request or action such as:
    1. routine requests for information
    2. meeting notices and reminders
    3. administrative notices
    4. invitations and responses
    5. interoffice activities
    6. “while you were out” messages
  3. Draft documents
  4. Courtesy copy informational messages – messages you receive to keep you informed on a matter, but you do not need to act on.
Email of record can be kept in subfolders to avoid being subject to the retention policy. However moving the relevant files to non-email storage online such as OneDrive or Box is the recommended option for long term storage of records.
  • Attached documents can be saved by right clicking and choosing Save As. Once the attachment is saved, you can safely delete the email or choose Remove Attachement to free up space in your mailbox.
    Save Attachment
  • If you need to save an entire email, simply drag the email out of Outlook to your desktop or folder you would like to save to. The email can be opened later in Outlook. Once saved, you can safely delete the email from your mailbox knowing the message is saved eleswhere.

Can I request additional storage?

Exceptions to the 25GB mailbox quota and 35MB message limit cannot be made. Please use cloud storage options like Box for storing and sharing large files. For example:

  • Save the file you would like to attach to Box, either through Box Sync or Box Drive.
  • Once the file is uploaded, select the file and click Share in the upper right.
  • You can invite collaborators, or copy a direct link to add to the email.
  • Sharing files via Box saves space in both your mailbox and the recipient's.

What can I do about Junk and Spam?

Junk and spam email can be deleted, automatically filtered, or reported to Information Security. For more information, please see the Spam and Junk Mail Frequently Asked Questions.

How do I get help?

If you have questions, need to report an IT issue, request a new IT service, or require additional help please visit