Errors with one disc in the Star Trek TNG box set

[sploo]

I picked up a used box set of all of the Star Trek TNG episodes on blu-ray (2020 CBS Studio). I've only got one old PC that has an (old) blu-ray drive so I wanted to use MakeMKV (v1.18.2, on Windows) to rip the discs to watch on another PC.

Of the 41 discs, 40 went well, but I'm unable to extract a couple of the episodes from one disc. There's no obvious signs of damage on the disc.

The blu-ray drive is a Lite-On iHBS112 2, which initially had firmware CL04. I upgraded it to the latest (PL06) but it still fails the read the disc. I've attached the log files from a CL04 and a PL06 run.

I tried an alternative technique I spotted on the forum: start a backup with MakeMKV, uncheck the decrypt option, let it run until it gets to the first m2ts file, stop the backup, quit MakeMKV, delete the incomplete BDMV folder and drag-and-drop the BDMV folder from the disc to the backup folder. Eject the disc, start MakeMKV, select File>Open Files and double click the discatt.dat file created by the previously cancelled backup.

When copying the BDMV folder I had to retry a few times, but it did eventually succeed. However, the MakeMKV still couldn't get all the episodes from the copy of the blu-ray in the backup folder.

Based on the above - is it more likely to be a bad disc, or my old blu-ray drive that's the problem?

[Woodstock]

More likely a dirty disk. I've ripped the entire TNG series on BD in the past (and will be again soon), so I know it works.

[sploo]

I had given the disc a gentle clean after the first failed attempt, but unfortunately that didn't made a difference.

As I'm not the original purchaser of the set I guess I might be out of luck in getting that disc replaced.