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Mozilla Thunderbird must be installed on your computer. The program can be installed by following these instructions.  You must have an administrative account to install software on your computer. If you do not have administrative privileges, please contact DECS and we will install it for you.

Checking Attachment Size

  • Thunderbird allows users to sort by messages with attachments. To do this, choose View in the top toolbar. Then scroll to Sort by in the new menu. This will bring up another menu. Select Attachments.

Screenshot of Thunderbird Attachments menu option

  • Messages with attachments will appear at the top, while messages with no attachments will appear below them.
  • To display the size of each message, click on the small button on the far right of the bar that has Subject, Sender and Date already listed.

A selected message in a Thunderbird inbow

  • In the menu that appears, select Size.

Screenshot of the "Size" menu option

  • A new column will appear listing each message's size. The size of each message indicates how much space it takes up in your inbox. If a message is larger than 10MB, its attachment should be saved to your M:drive; then the message should be deleted. Further instruction for this is available below.
  • To delete messages, select the message(s) to be deleted and press the Delete button on your keyboard. Multiple messages can be deleted at once if you hold the control key, abbreviated Ctrl on the keyboard, while selecting all of the messages you wish to delete. After you have finished selecting the messages to be deleted, press the Delete key.

Screenshot of selected messages in a Thunderbird inbox

  • Next, delete any unwanted messages and move other messages to mailboxes/folders other than Inbox. These mailboxes are located on your M: drive. Please click the link for more instruction.


Saving Attachments to M:drive

  • Select the message with an attachment to download. The message contents should appear in the viewing pane. Messages with an attachment will have a bar at the bottom of their body. Under the bar will be the name of your attachment.

Screenshot of a Thunderbird email with the attachments bar circled

  • Right-click on the name of the attachment to open a new window.

The "Save As" menu option for Thunderbird attachments with an arrow pointing to it

  • Click Save As... to open a new window and go to a location on your M:drive to save the attachment. Make sure to save the attachment somewhere on your M: drive where you will be able to find it later.

The "Save Attachment" window

  • Now click the Save button and your file will be copied to the desired location.