[Edit: see post #4 for how I was able to fix the problem.] I have a 2018 Mac mini and I have this SSD as an external drive in a third party enclosure (TEKQ), which I successfully formatted Extended (Journaled). I decided to reformat it APFS and I'm running into significant problems. I got as far as what you see in the photo (note "Container Disk3", no name), but can't go further. Disk Utility and Terminal both hang indefinitely when I try to create an APFS Volume or erase/reformat to another format, regardless of what format I choose, including efforts to return to Extended (Journaled). I've even tried Paragon Software's NTFS for Mac to see if I could format NTFS, but with the same result. Running Disk Utility First Aid initially said that there is a corruption problem. At that point, I ran Recovery First Aid, which said that the problem was fixed. Now Disk Utility First Aid also hangs. Looking at old threads, a couple of people have fixed this kind of problem, or similar, by formatting on a Windows or Linux machine, and then reformatting on a Mac. To try that, I need a computer with a TB3 port, but calls today to friends with Windows computers came up blank. On the upside, it looks like I inspired one friend to buy himself a new laptop Any ideas, brilliant or otherwise? Thanks.