www.makemkv.com

I've ripped most of my Blu-ray collection to a hard drive but recently started having trouble. Every Blu-ray I try rips without error but the resulting MKV file is unplayable. I've tried blu-rays from several manufacturers to be certain (Moana, Fantastic Beasts and Where to Find Them, The Thing, etc). Windows doesn't read it as a video file - there is no 'length' value in the windows explorer details. DVD's ripped from the same Blu-ray drive rip just fine. The lack of an error message is frustrating, so any ideas on what to investigate next would be appreciated. Thank you.

Windows Explorer does not natively understand MKV files. And the Windows Media Player is limited in the video encodings that it can play.

Have you tried playing the files with a more advanced player, such as VLC from videolan.org?

The VLC video player does work, thank you. Oddly enough other MKV files on my system are recognized as video files by Windows and play in the Movies & TV app. They are ones that I compressed using handbrake however. I'll try compressing and see if that works.

The compression of the file failed; Handbrake crashed during the process leaving an incomplete m4v file. This has been consistent with my recent rips as well. Because of the crash the Handbrake log file is incomplete so I'm not sure why it crashed. Is there any way to examine the structure of mkv files and compare them so I can determine if there's a difference?

MediaArea dot net offers a tool called MediaInfo which will display the contents of an .mkv container, et al.. It ought to, at least, let you see if there's any commonality with the 'bad' files.

It's been a while but I finally got a chance to take a look at this issue again. The mediainfo tool didn't show any problems with the files that cannot be played by Windows 10 (either by the Movies & TV app or by Plex). For reference, I ensured that the blu ray drive could still play the blu rays I'm trying to rip, the firmware on the drive is current, and that the windows 10 registries on the machine were up to date. The real killer is that these files cause Handbrake to crash so I can't compress them even if I did use the VLC player that worked earlier. I've tried ripping using the version of makemkv I started this process with (1.10.0) but got the same negative result. In addition I downloaded a trial of DVDFab and ripped with that and got the same 'corrupted' MKV file. So this definitely has something to do with either my hardware or my OS or something, but I just don't know what to look for next. I don't want to have to buy a new Blu Ray drive to eliminate that possibility. Any ideas would be a huge help. Thanks.

I am quite fond of the K-Lite Codec pack, can be downloaded easily from free-codecs.com.
It also installs a little plugin so that Windows Explorer shows thumbnails of all your videos. It can remove the little annoying "filmstrip" from the thumbnail as well.
Media Player Classic HC is a minimalist media player that comes with it as well but is very functional for media files.
The difference between the regular K-Lite and K-Lite Mega are only a couple of megabytes of data and the installer will ask you what you want to install anyway.

Make sure you are running Java, otherwise Blu-rays with BD+ may result in corrupt rips, which Handbrake may not like.

Info here: /svq

Actually, BD+ decoding does NOT require the JRE - MakeMKV has "enough" of a Java interpreter for BD+.

Obfuscation, on the other hand, needs "more POWER!", so the Java Runtime Environment needs to be installed.