Assuming you are using IMAP (which is the default), it will leave the attachments on the server and only delete the local copy. CleanMyMac X has a tool that will look through your email and find large attachments. There aren’t a lot of options for deleting your mail attachments from the local copy while leaving them on the server, but thankfully there is a piece of software that does this. So unless you are keeping a historical email archive for personal or legal reasons, it’s usually safe to delete them. What usually takes up the most space in your mailbox are all the attachments (such as ZIP files, images, or videos), many of which you likely saved in other places on your Mac when you initially received them if they were important. Option 1: Clean Up Mail Attachments Using CleanMyMac If you’ve found that Mail is using up more space than you expected, it’s time to take action. When you’re done, close the Mail Info window and the Library window in Finder. Locate the Mail folder, right-click or Control-click it, and select “Get Info.” You’ll see how much space is being used by the Mail app for your user account, listed under “Size.” To see it, open Finder, click “Go” in the menu bar, and choose “Go to Folder.” Type ~/Library into the box and press Return. This is where the Mail app stores its data for each user.

Each user account on your Mac has a Mail directory in their Library folder-that’s ~/Library/Mail, or /Users//Library/Mail. To see how much space you might be wasting on email attachments, you’ll need to check the source.

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