How to Free Up Mail Storage on Mac with Safe & Best Guide?

Mark Regan
Published: April 8th, 2026 • 6 Min Read

Want to free up Mail storage on Mac? This guide will help you understand the best methods to do it. Sometimes the Apple Mail mailbox runs out of space and becomes slow due to the large number of stored emails. In such situations, it becomes important to clean Mac Mail storage to ensure smooth accessibility.

Email communication is an important part of both personal and professional life. Several users rely on Apple Mail as it provides a simple interface, smooth integration, and a strong security with the macOS ecosystem. However, after using Apple Mail for months or years users often notice that their mailbox starts consuming a large amount of space.

This usually happens when Apple Mail stores email messages, attachments, cached files and download content locally on your system. Meanwhile, these files accumulate and can occupy several gigabytes of space on your Mac Machine. In this blog, we will discuss some real scenarios of Apple Mail’s full storage and how to free up Mail storage on Mac.

Some Real Scenarios Where User Need to Free Up Mail Storage on Mac

Before jumping to the method to clean Mac Mail storage safely let us first discuss the reasons that a user need to free up storage space in Mac Mail:

Working on large project files and emails notices that their Mac storage is almost full due to Apple Mail’s attachments alone consuming several gigabytes.
Someone who has been using Apple Mail for 4 to 6 years at least may have thousands of emails stored locally including newsletters, multiple attachments and promotional messages.
Employees generally receive PDF reports, presentations, ZIP files, or images that are often too large and consume too much space that you get Apple Mail storage full notification.
Sometimes, mailboxes fail to sync correctly because the local cache becomes too large or corrupted, cleaning up the storage may help you to fix it.
As soon as the mailbox database becomes extremely large, the Apple Mail application may start lagging while searching something or open very slowly.

Manual Ways to Clean Mac Mail Storage

Below are some manual techniques to deal with Apple Mail storage full notification and free up storage space in Mac Machine with ease.

#1. Delete Large Emails and Attachments

Open Apple Mail on your Mac Machine.
click on any mailbox such as Inbox.
Click on View >> Sort By >> Size.
Identify emails with large attachments.
Now, delete all unnecessary emails.

This way you can remove high-storage consuming emails quickly.

#2. Remove Downloaded Large Size Attachments

Firstly, open any email that contains attachments.
Right-click on the attachments.
Select Remove Download option.

This way you can remove attachments that are stored locally but keep the emails accessible on the mail server.

#3. Empty the Trash Folder

First, open the Apple Mail.
After that, select the Trash mailbox.
Now, click on Mailbox >> Erase Deleted Items.

This way you can permanently delete emails and free up storage space.

#4. Cleanup Mail Download Folder

Open Folder.
Now, click on Go >> Go to Folder.
Enter destination path “~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads”
Review and delete unnecessary attachments.

This method helps you to free significant disk space, especially if you receive many attachments.

#5. Rebuild Apple Mail Mailbox

Open Apple Mail.
Select the mailbox you want to rebuild.
Click on Mailbox >> Rebuild

Apple Mail will re-index messages and will free up mail storage on mac that will reduce storage usage.

#6. Remove Old or Unused Mail Accounts

First open System Settings.
Go to Internet Settings.
Select the unused email account.
Lastly, remove it from Apple Mail.

This way you can prevent unnecessary mailbox synchronization and can prevent Apple Mail storage full notification in future.

#7. Archive Old Emails Outside Apple Mail

First, select emails you want to archive.
Now, drag them to a local folder in Apple Mail.
Export them for backup.

This way you can reduce your active mailbox size to better accessibility.

Although the manual methods discussed above can help you to reduce mailbox size, they also come with several limitations. These methods may work for small mailboxes, but when you are dealing with a large number of emails and databases they often become time-consuming and inefficient. Here, you need to choose a permanent solution and we would suggest you backup your entire mailbox or just some important emails along with attachments and clean mac mail storage.

Best Way to Free Up Mail Storage on Mac Mail

Apple Mail Converter offered by BitRecover is one of the best solutions to help you clean up Apple Mail storage with ease and safety. Used and recommended by industry professionals to export all the Apple Mail data from mailbox efficiently and create a backup of all the important conversations can help you to free a lot of space from your mail on Mac.

You just need to download this solution and proceed with the quick and easy steps to preserve your important personal and professional conversations and documents.

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How to Use this Solution on Your Windows System?

Firstly, download and install the software on your Windows system.
After that, choose Select Files and Select Folders to upload your Apple Mail data into the software panel.
Now, preview and check all the uploaded Mac Mail data to free up mail storage on mac.
Now choose any format to backup all your important emails along with attachments in your storage.
Finally, choose the Destination Path and a new name from File Naming Option.
Apply Advanced Filters from Filter options if required.
Lastly, proceed with clicking on the Convert button for an accurate result.

Why Use this Solution Over Fixing it Manually?

Manual ways are time-consuming when you need to free up mail storage on Mac.
It allows you to download all the Apple Mail emails along with all the attachments in bulk as well as selectively.
Helps you to even export Apple Mail into EML, PST, PDF, DOC etc. file format as per convenience.
Offers quick and short steps to export all the data on Mac Machine as well as Windows system.
Keeps the entire data intact along with the formatting and maintains the originality as well.
Offers save all the downloaded attachments from emails into some file formats for an easy access.

Need More Help?

The above mentioned method is the best way if you need to free up mail storage on Mac or even on Windows system. We have discussed some manual techniques as well to avoid Apple Mail storage full popup. You can use whichever method suits your requirements. If you need any help or more information regarding the process or solution feel free to reach out to our Technical Support Team anytime, They are available 24/7 to assist you.