www.makemkv.com

I backed up a UHD disc, apparently successfully. But at the beginning of the process MakeMKV 1.17.8 reported that it could not load the content hash table and skipped those files. No errors after that. The backup finished. The copy seems fine based on spot-checking it by playing various playlists. What is going on here?

Messages:
Downloading latest HK to XXXXX ...
Failed to load content hash table, unable to verify integrity of M2TS files.
File "/MAKEMKV/AACS/ContentHash001.tbl" was skipped
File "/MAKEMKV/AACS/DUPLICATE/ContentHash001.tbl" was skipped

Drive Information
Current profile: BD-ROM
Manufacturer: ASUS
Product: BW-16D1HT
Revision: 3.10
Firmware date: 2119-01-04 10:14
Bus encryption flags: 1F
Highest AACS version: 81

LibreDrive Information
Status: Enabled
Drive platform: MT1959
Firmware type: Patched (microcode access re-enabled)
Firmware version: 3.10
DVD all regions: Yes
BD raw data read: Yes
BD raw metadata read: Yes
Unrestricted read speed: Yes

Disc Information
Label: TURTLE_ODYSSEY
Timestamp: 2019-09-30 12:43:32
Protection: AACS2.0/C v72
Data capacity: 62.15 Gb
Disc type: BD-ROM UHD
Number of layers: 2
Bus encryption flags: 80

I also just encountered this error this weekend. "Failed to load content hash table, unable to verify integrity of M2TS files.". I was going through 14 brand new UHD discs and "Once Upon a Time in Hollywood" was the only issue. I have tried cleaning and using other OS's. Still no luck.

The content hash table is part of the blu-ray/UHD specification. It contains hashes of every chunk of content on the disc. It is the thing MakeMKV uses to verify that what it reads off the disc is correct.

My guess is MakeMKV was unable to correctly read the content hash table for some reason. So, it performed the rip or backup without the aid of the content hash table which means MakeMKV didn't verify that what was read from the disc was correct.

Probably the rip or backup is fine.

However, if it bothers you, gently cleaning the disc and trying again is probably the best course of action.

After that unusual event, I did clean the disc (again) and copied it again using another drive, a Pioneer model. This produced the exact same results: same failure to load content hash table, and the copied files were identical in both copies as verified by comparing hashes using the utility hashdeep.

I assume it is this disc you're talking about? https://ultrahd.highdefdigest.com/79582/turtleodyssey4kultrahdbluray.html

I've never come across a blu-ray or 4K UHD without a content hash table, but I suppose it is possible the disc just doesn't have one at all.

Since you've ripped it twice on two different drives and gotten the same output both times, I would guess you've gotten a good copy.