www.makemkv.com

Hello,
I have a M1 Mac mini and I was trying to copy my brand new, 4K LOTR disks (extended version) to my NAS. Several of the Disks are showing a "fatal error" and causing the program to close. One of the two seems to look pristine, the other one has a roughly ½ inch scratch in the middle of the disk. I am including the information from Make MKV regarding the drive. etc.
Any help would be appreciated!

You posted in the DVD section instead of UHD.

Clean the discs with warm water and liquid soap and afterwards again with a microfiber cloth. UHDs show some invisible film that creates read errors - even if they look immaculate.

There's not a lot to go on in the original post. Generally, I don't think MakeMKV is supposed to get a 'fatal error' during operation.

viewtopic.php?f=8&t=24137

The above thread is someone who had a fatal error recently. Some of the debug steps in that thread might apply here.