I keep all my old scanned records in encrypted APFS disk images, one disk image per year. I do have my Mac filesystem encrypted too, which protects against unauthorized access if the machine gets lost or stolen. However, by keeping these records on encrypted disk images that I only mount when they’re in use, I add a bit of protection against rogue software exfiltrating the data.

It’s probably absurd to use this kind of protection for simple stuff like old utility bills, but a little paranoia can prevent a large headache, as the saying goes^*.

Today, I wanted to look at an old file, and was getting “Permission denied” errors from the Preview app. Looking at the file information from the finder (and then from the terminal) showed permissions were fine. I tried double clicking on the file, and got the permission denied message — including the name of a different file than the one I was trying to open. [o.shit.emoji]

I ran Disk Utility’s “first aid” on the image, and that said everything was fine, but I continued to get the error. I ran fsck_apfs on the image too (specifically, hdiutil attach -nomount /path/to/my/file and then fsck_apfs -y /dev/disk6s1). That’s probably what Disk Utility was doing under the hood, but I figured I’d try it anyway. Same error.

Then I said “[bleep] it!” and rebooted the system. Mounted the disk image, and everything’s fine. Computers suck 🙁

^* It does go like that, doesn’t it?