Mail has stymied some people after they updated macOS and tried to open attachments. Instead of opening the attachment in the corresponding app, the app says “you don’t have permission to view it” or “access to File name was denied.” However, if you drag the file from Mail to your desktop or another Finder window, you’ll find that you can open it without any errors.

The solution could be as simple as fixing the permissions on the deeply nested folder that Mail uses to store attachments. Here’s how to do it:

1. In Finder select Go > Go to Folder.
2. Paste in the following: ~/Library/Containers/com.apple.mail/Data/Library/
3. Select the Mail Downloads folder.
4. To choose File > Get Info.

Under “Sharing and Permissions” you should see name (I) and Read and write next to it. If you don’t, click the padlock in the lower right corner of the Info window and authenticate as prompted by macOS.

Then do one of the following in the Sharing and Permissions section of the Info window:

• Click the pop-up window under “Privileges” next to name (I) entry and choice Read write.
• If your name does not appear in the Name column, click the + (plus) sign, select your name, and click To choose. Then select Read write in the Privileges column on the right.

Now click on the circled “More” button (… circled) at the bottom, select Apply to closed items and press GOOD confirm.

This should fix the permissions issue for most people. If that doesn’t work, I recommend restarting macOS Recovery and running Disk Utility Disk First Aid as described in these steps.

If this still doesn’t fix the mail attachment issue, I suggest a non-destructive in-place reinstallation of macOS. Be sure to create a full Time Machine backup or equivalent before reinstalling macOS.

This Mac 911 article is in response to a question posed by Macworld reader Worth.

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