www.makemkv.com

I installed 1.18.3 and ripped the BD ("Collector's Edition") to a thumb drive. It ran and completed normally. But none of the files will play in VLC. For good measure, I also tried 5KPlayer.

I have a physical BD player with a front USB port (the reason for ripping to a thumb drive in the first place) and I can play a variety of file formats including (decrypted) m2ts. Even vob files from a DVD. It tells me the files are corrupt although clicking around I have seen a studio logo play. But that's all.

Are you trying to play .mkv files that MakeMKV created?

Well, actually .m2ts.

I rip a movie and I get
title > BDMV > STREAM > ***.m2ts (lots of them)

If it's not an obfusacted BD, typically the largest m2ts file will be the movie in its entirety and playable with VLC or with the physical BD player.

I just copied a previous rip (biggest file) to a thumbdrive and walked it to the BD player and it is playing just fine.

Song Sung Blue was the first use of that version of makemkv (on a different machine). I will run a test with a different BD.

Followup:

It turned out to be a simple resolution. My first attempt to rip SSB on 1.18.2 produced errors because SSB uses some newer form of encryption. I installed 1.18.3 on two other machines and both produced unreadable results. After much head scratching and test rips of other disks on both versions I finally realized that I'd failed to check the decrypt files box on the new installs. So I was getting encrypted files which is why they would not play. I just looked and once the box is checked, it does stay checked on future uses just as in the past. So with decryption turned on, no problem with playback.