Well, there's ReFS as well. That experience suggests there are issues that the author might come up against following boot: Case insensitive lookup (NTFS has th

Well, there's ReFS as well. That experience suggests there are issues that the author might come up against following boot: Case insensitive lookup (NTFS has the option for case sensitive subdirectories but that probably doesn't matter), Mark of the Web/SQL Server (Alternate data streams support), UWP/Microsoft Store apps support (IIRC requires FS encryption support via a specific interface), DLT (Object IDs), getting DISM to work for updates... It's cool to get this far, full support will probably need a bit more work.