Everyone is issued a maximum amount of email space and once this quota is reached at 100%, you will be unable to receive any other mail. This document shows you how to save your email to a local disk on your computer's hard drive and remove it from the mail server, thus conserving space on the mail server. At the same time, this also allows you to have a local archive of your email.
This document assumes you are using Thunderbird on a Macintosh OS platform. It is also assumed that Thunderbird has been configured to use the IMAP protocol.
The first step in reducing your disk space usage should be cleaning up your current email. Delete any emails that are no longer needed, especially emails with attachments.
The Thunderbird window is composed of three frames. The frame on the left displays your mail folders, both local and online. This is the frame we will be most concerned about for saving your email messages. In the figure below is an example of the Thunderbird window. Notice that in the frame on the left, there are two major divisions among the folders. The first is your online folder. In this example, we've named it UH Email. The second is called Local Folders. The former is your email that is stored on the server and the latter is your email that is stored on your computer's hard drive. The UH Email folder is limited by your respective email quota.
Create a new local folder where you will store the email you no longer need to have online. To create a new local folder, go to the File menu, click New, and then click Folder. See figure below.
Next, Give the folder a name, and then click on Local Folders. Be sure to click on Local Folders to ensure the new folder will be created on your local hard disk. Click on the OK button to create the folder. See figure below.
Now, select the email you wish to move offline and have saved in your local folder. Simply drag the emails that are to be saved into the new local folder that was created in the previous step. In the figure below, the two email messages from firstname.lastname@example.org was selected and moved into the new local folder, Saved Email.
To verify that the email has been saved to your local hard disk, click on the new folder you created (Saved Email). The saved email should be displayed in the frame on the right.
Once the emails have been moved, it will disappear from the UH Email server.
By default, when deleting an email in Thunderbird, it moves the message into the Trash folder. This Trash folder is located on the mail server and it counts toward your quota. To delete your messages in your Trash folder, go to the File menu and click on Empty Trash.
If you wish, you may change the delete settings. There are three options: Move it to the Trash folder (default), mark it as deleted, or remove it immediately. The first two options (Move it to the Trash folder and mark it as deleted), needs another step to remove the messages from the mail server (to reduce your quota). To change this setting, go to the Tools menu and click on Accounts Settings.
If Thunderbird is configured to mark email as deleted, you should see a circle with a line through it next to the email that has been marked as deleted.
To delete these messages, go to the File menu and select Compact Folders. This will remove the messages marked for deletion from your mailbox on the mail server and lower your disk space usage.
There may come a time when you wish to move the emails you saved onto your local hard disk back online to be accessed from different locations. The process of moving the email back online is very similar to the process of saving them to your local hard disk.
Go to the File menu, click New, and then click Folder. Next, Give the folder a name, and then click on UH Email. Be sure to click on UH Email to ensure the new folder will be created on the server. Click on the OK button to create the folder. See figure below.
Now, select the email you wish to move online to be accessed from multiple locations. Simply drag the emails that are to be uploaded into the new online folder that was created in the previous step. In the figure below, the two email messages from email@example.com was selected and moved into the new online folder, Upload Email.
That's it, your email is now back online. The email messages have been moved from the local folder and placed in the newly created folder online. These email messages now count against your quota, but they are able to be accessed from multiple locations.