3 Tips to Save (and Regain) Disk Space in Mac Mail

Mac Mail logo over old-fashioned card catalog

You don’t normally think of email as taking up space, but in actuality it can eat up quite a bit of drive space on your Mac. While this probably isn’t an issue for those of us running hard drives of 500 GB and above, many Mac owners have opted for smaller, faster Solid State Drives (SSDs) that can fill up quickly.

Sure, your Gmail or work email may be stored on a server, but when Apple’s Mail app downloads them for you to see, the messages and any attachments usually come along for the ride. So how do you keep accessing emails via the app while keeping storage at a minimum?

The first step is understanding why your storage space is being taken up. Then we can get it fixed without any stress. Here’s how.

See How Much Space Mail Takes Up

So how much space is Mail taking up on your machine? Users of Gmail with its nearly unlimited storage often don’t think about this, but when your emails are downloaded to the Mac Mail client, they stick around.

To see how much space your email is taking up, click on your desktop and then the Go menu. From here, select Go to Folder and enter this: ~/Library

Selecting Go to Folder in Mac Finder menu

This will open up your Library folder. Scroll down until you see the Mail folder. Right-click on it and then select Get Info.

Context menu for a folder in OS X Yosemite

Depending on how much mail you have and how many accounts you’re using, this can take up to a minute or so. Once it loads you’ll be able to see how much space is used up under the Size category. In the example below, the combined email accounts take up 5.8 GB.

Data for Mail folder in Get Info box

Now that you know how big your Mac Mail app is, it’s time to get cleaning.

1. Disable Attachment Downloads

The majority of space taken up on your Mac in regard to mail is attachments. Text emails don’t generally take up a lot of space, so it’s not the number of messages we’re worried about, but the attachments themselves.

With the Mail app open, click on the Mail menu and then Preferences. With the Preferences window open, click on the Accounts tab. You should see a list of email accounts to the left, and some settings to the right. Since we have to do this for each account you have, just start at the top and work down.

Click on the Advanced tab with one of your email accounts selected and you should see a checkbox next to Automatically download all attachments. Uncheck this box. Now all future email attachments will still be available; you’ll just have to download them yourself each time.

Accounts tab in System Preferences window

Once you’ve done this for each account in your list, all future email attachments will only show once you’ve chosen to download them.

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2. Limit IMAP Messages

Tip #1 is a great way to limit space requirements for future emails, but there’s a second approach to this issue, too. Instead of stopping the automatic download of attachments, why not just limit the number of emails your computer downloads from the server?

For this tip you need to look outside the Mac Mail app and to your email client. For example, Gmail gives you the ability to limit the number of emails that get downloaded in IMAP folders. This means you can tell Gmail to only allow the Mail app to store a certain number of messages. They’re still available in Gmail – you just can’t get them in the Mail client.

With your Gmail account loaded in your Internet browser, click on the gear icon in the upper right corner. From here, click on Forwarding and POP/IMAP. Scroll down until you see Folder Size Limits. By default, this is set to not be limited. To limit it, just select the other option and choose how many messages you want to have access to in Mail. This will keep your Mail inbox from using important storage for old emails that you don’t access often.

Forwarding and POP/IMAP tab in Gmail settings

3. Delete Emails From Old Accounts

The last step to clear up some space from Mac Mail is to get rid of old email accounts. If you’ve ever had an email account in Mail that you’ve removed and are no longer using on your Mac, there are probably still old messages stored there and taking up space.

Head over to the Mail folder on your Mac using the steps we outlined in tip #1, but this time actually open the Mail folder. In it, you’ll probably see a folder called V2; double-click this. Inside that folder you should see a folder for each of your email accounts, most of which start with IMAP-. If you see any here that belong to email accounts you no longer use, you can simply delete them and get that storage space back.

Storage folders in Mac Mail

Don’t delete any account folders that you’re currently using, though. While doing this won’t affect emails on the server, it can cause errors with your account on your Mac, so it’s best not to do it. If you want to delete emails and attachments from active accounts, do it inside the Mail client, or on the server.

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