www.makemkv.com

All good.
It was just the discs.
Today Tenet exchanged a new disk ran without problems.

UHD disks are very sensitive.

The L drive remains off with both USB connections of the Y-cable. I don't have USB-C for testing.

Version 1.15.2 same problems as with version 1.15.4


These errors came with Tenet 4K:

Failed to save title 1 to file /Users/punisher/Movies/Tenet/Tenet_t01.mkv
Encountered 18 errors of type ...

I also set the disk speed to code "0 = 8"
set but unfortunately exactly the same mistakes.

I have the same problems with an archgon bu40n firmware 1.00.
Drive is 2 days old

Have 3 different UHD disks always tried error read between 20 and 30 GB.
UHD Movies:
Tenet
King Arthur
Justice League

Also tried several platforms.
Windows 10
Big Sur MacOS

but only the MKV software 1.15.4


Blue ...