If you have a Mac external hard drive, it is accessible by all users on your Mac. When you mount it, it is pretty much open game. If you have multiple users, they will be able to access it too unless you take action. Even if you encrypt your external hard drive, if it’s on the same Mac, that’s the Mac that opens it up to be viewable. It’s only when you connect the drive to another computer is when it’s secure.
Here’s how to secure your external hard drive against other Mac users on your computer:
- Limit permission or access to only you
- Right-click drive->Go to Sharing & Permissions->Set Everyone to No Access
- Make sure any other Users besides yours is set to No Access
- Set up your username to Read & Write
These steps will ensure only your user account is set up to access your external hard drive. This will come in handy if you share your Mac with family, friends, co-workers, etc. As a side note, please remember to back up your external hard drive regularly to avoid Mac data recovery issues.