How to Clear Mail Downloads and Attachments on Mac

Why Apple Mail Accumulates Tens of Gigabytes of Hidden Storage

Most Mac owners assume that reading an email keeps its contents on the mail server. You glance at a contract sent as a PDF, close the message window, and assume your internal storage remains untouched.

In reality, Apple Mail behaves very differently. To make attachments open instantaneously and allow Quick Look previews to render without network lag, macOS downloads and extracts every viewed attachment into a hidden user directory. If a colleague sends a 150MB video clip or a designer sends a 200MB zip archive, double-clicking that file writes 200MB of permanent data directly to your internal solid state drive.

Even worse, macOS never prompts you to delete these cached files when you close the email. Over two or three years of everyday communication, your Mac quietly accumulates thousands of forgotten invoices, client drafts, software installers, and holiday photos. When your internal SSD drops below 15GB of free headroom and triggers a startup disk almost full alert, this hidden attachment vault is often responsible for a massive portion of the problem.

Furthermore, these files often spill over into generic categories inside macOS System Settings. Many Mac owners searching for ways on how to clear System Data on Mac discover that half of their mysterious System Data is actually obsolete Mail cache debris that macOS refuses to categorize clearly.

The 3 Places Apple Mail Hides Storage on Modern Macs

If your Mac is feeling cramped, Apple Mail typically distributes its storage footprint across three separate locations inside your user Library:

Is It Safe to Delete Mail Downloads on Mac?

The most common question everyday Mac owners ask is simple: "If I delete these files, will I lose my emails or delete files off the server?"

The answer is an emphatic NO.

Modern email relies almost entirely on IMAP or Exchange protocols (including Apple iCloud Mail, Google Gmail, Microsoft Outlook, and corporate email systems). When you connect your account, your email provider maintains the authoritative master vault of all incoming and outgoing messages in the cloud.

The files inside your local Mail Downloads folder are merely cached previews. When you empty this folder:

• Your email messages stay untouched in your inbox, archive, and personal folders.
• All original attachments remain stored safely on your mail provider servers.
• If you ever open that three-year-old email again and click the attachment icon, Mail will simply fetch a fresh copy over your internet connection in a couple of seconds.
• Your sent messages, drafts, signatures, and account passwords remain completely unaffected.

For an in-depth look at what user scratch files are safe to purge across your Mac, explore our complete guide on whether you can delete Library caches on Mac.

Step-by-Step: How to Clear Mail Downloads in Finder

If you prefer to clean these cached files manually without third-party software, you can navigate directly to the hidden folder using standard macOS Finder tools:

~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads

Follow these five simple steps to complete the cleanup:

1. Quit Apple Mail: Ensure the Mail app is completely closed. Press Command + Q while Mail is active, or right-click the Mail icon in your Dock and choose Quit. Closing the app prevents file locking errors while cleaning.
2. Open the Go to Folder Window: Switch to Finder. In the top menu bar, click Go > Go to Folder... (or press the keyboard shortcut Command + Shift + G).
3. Paste the Target Path: Copy and paste the following folder location into the search field and press Return:
   ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads
4. Select and Trash the Cached Files: Finder opens a window displaying subfolders with random alphanumeric names. These contain your cached attachment files. Press Command + A to select everything in the folder, right-click, and select Move to Trash (or press Command + Delete).
5. Check the Legacy Location: Repeat the same process with the legacy path:
   ~/Library/Mail Downloads
   If this folder exists on your drive, select its contents and move them to Trash as well.
6. Empty the Trash: Right-click the Trash icon in your Dock and click Empty Trash to finalize the recovery of your disk space.

When you relaunch Apple Mail, your inbox will look completely normal. All of your emails will be present, but your internal drive will suddenly have gigabytes of restored breathing room.

How to Manage Mail Storage in macOS System Settings

Modern versions of macOS offer a native storage breakdown that gives you a high-level overview of application sizes:

1. Click the Apple menu in the top left corner of your screen and select System Settings.
2. In the left sidebar, click General, then click Storage on the right.
3. Wait a moment while macOS calculates your drive allocation. Scroll down the list of categories until you locate Mail.
4. Click the small (i) Information icon next to Mail.

How to Stop Apple Mail from Hoarding Attachments Automatically

Clearing your existing cache is a fantastic instant fix, but unless you adjust your account configuration, Apple Mail will slowly start filling your drive again with every new email you receive.

You can instruct macOS to be much more conservative with attachment downloads:

1. Open the Mail app on your Mac.
2. In the top menu bar, click Mail > Settings... (or press Command + ,).
3. Click the Accounts tab at the top of the preferences window.
4. Select your primary email account from the left sidebar.
5. Click the Account Information tab.
6. Locate the Download Attachments dropdown menu. By default, macOS sets this to All.
7. Change the setting to Recent or None.

Setting this option to Recent instructs Mail to only download attachments from emails received within the last few weeks. Choosing None instructs Mail to only keep message text locally, fetching attachment data on-demand only when you explicitly click an attachment icon. If your Mac has a compact 256GB SSD, this simple adjustment can save you 15GB to 30GB of space every single year.

If you are trying to decide whether your current storage tier is sufficient for your daily workflow, try our interactive Mac Storage Needs Calculator to evaluate your app and document footprint.

The Effortless 1-Click Solution: DiskCompanion Smart Clean

While hunting through hidden Library folders in Finder works, doing it by hand every few months is tedious, and one wrong click inside ~/Library can accidentally damage an active application database.

We designed DiskCompanion to give everyday Mac owners complete peace of mind. Instead of forcing you to remember complex directory paths or type commands into Terminal, DiskCompanion automates the entire process safely:

In addition to clearing mail clutter, repeated attachment saves frequently spawn identical files across your Desktop and Documents folders. You can also explore our guide on how to find and delete duplicate files on Mac to clean out redundant copies in a few clicks.

Comparison: 3 Ways to Clear Mail Storage on Mac

Here is how the three cleanup methods compare across safety, disk recovery, ease of use, and automation:

Whether you choose to clear your Mail Downloads manually through Finder or automate the process with DiskCompanion, clearing out this hidden attachment cache is one of the fastest, safest ways to reclaim valuable gigabytes on any Mac.