Mail has thwarted some people after they upgraded macOS and tried to open attachments. Instead of opening the attachment in the appropriate application, an app claims “you don’t have permission to view it” or “access file name was denied.” However, if you drag the file from Mail to the desktop or into another Finder window, you’ll find that you can open it without errors.
The fix could be as simple as correcting permissions on the deeply nested folder Mail uses to store attachments. Proceed as follows:
Choose in the Finder Go > Go to Folder†
Paste in the following: ~/Library/Containers/com.apple.mail/Data/Library/
Select the Mail Downloads folder.
To elect File > Get Info†
Under Sharing & Permissions you should see name (Me) and Reading & Writing next to it. If you don’t, click the lock icon in the lower-right corner of the Get Info window and authenticate as prompted by macOS.
Then, in the Sharing & Permissions section of the Get Info window, do one of the following:
Click on the pop-up under Privilege next to the name (I) enter and choose Reading writing†
If your name is not in the Name column, click the + (plus) sign, choose your name and click Select† Then select Reading writing in the Privilege column on the right.
Now click on the circled button more (… in a circle) at the bottom, choose Apply to Attached Items and click Okay to confirm.
This should solve the permissions problem for most people. If that doesn’t work, I recommend rebooting into macOS Recovery and running Disk Utility from Disk Utility as described in these steps.
If that still doesn’t fix the email attachments problem, I recommend a non-destructive reinstall of macOS. Make sure to create a full Time Machine or similar backup before reinstalling macOS.
This Mac 911 article answers a question from Macworld reader Worth.
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