CellWalk algorithm failed (structure protection is too tough

[VFRMan]

I was using MKV on a Green Room DVD, and received this error message on numerous titles.

Title #30 was added (18 cell(s), 1:34:47)
DEBUG: Code 10551303 at y}`3D]oYp|pF5hI*:29405752
DEBUG: Code 0 at y}`3D]oYp|pF5hI*:29406741
DEBUG: Code 0 at E2lW<:.ZKAmGf(i`sW:29394229
CellWalk algorithm failed (structure protection is too tough?), trying CellTrim algorithm
Cells 1-1 were removed from title start

Not sure if it's the DVD or the software. I've never seen this message before, and I was forced to update MKV to version 1.10.4 on Mac OS X when I opened the program. I really hate that the program will not load up or continue to function when there is a new update. All I get is some generic message about "version too old" and shuts down.

Anyway I updated the software, scanned the DVD and now getting this error on multiple titles. I'm attaching the log file.
Nope, never mind... no attachment, I tried and received "Sorry, the board attachment quota has been reached."

[Woodstock]

Don't worry about attachments - including the log in the text of the message is adequate, unless it is bigger than about 50K.

Debug codes often mean the drive is covering up for a problem. When asked to read part of the disk, it didn't return any error, but the data returned did not make sense. Mike has said this happens with some drives when they can "almost" read a sector, and, rather than say there was a problem, return what they were able to read. So MakeMKV tries different things (the debug codes) to make sense of it.

Sometimes it's harmless - the work-arounds worked, and you get an MKV file. Other times... not so much.

If the resulting MKV file is good (starts where it should, ends where it should, is the right length), I'd ignore the errors. If it doesn't generate an MKV file, though, I'd clean the disk, and try the rip again.