www.makemkv.com

I have a new disk (puppet master 4 bluray), looks perfectly clean, wiped it down with a shammy just in case and still a couple of failed hash check keep showing up. (Is a hash check like a double check of data?) Is ther any cleaning or topical supply that might help? Could it just be a bad disk? Never had one before

Also i have 3 drives and one seems to be working great (besides that one disk) but the other two not so much. One hits once in awhile but blurays only (no 4k anymore) and the other one keep crashing my laptop, i just upgraded to big sur...coukd that have reset my firmware?

I also notice they get really noisy sometimes, like something is grinding but the disk is fine. It stops once i eject and set it up again for awhile. Ive always assumed its just a bug but its happened more than usual since big sur upgrade.

http://www.makemkv.com/errors/hashcheck/

It is very unlikely that upgrading macOS to Big Sur changed the firmware on your optical drive. MakeMKV lists the firmware version for your drive, so it is easy to double check. Have you tried completely powering down the drives and powering them back on again? Inside the optical drive is a tiny computer. The only way that computer reboots is if power is completely removed. If the drive is in an external enclosure, it might have a switch on the back or you can unplug the power/USB cord.

The grinding noise is likely the drive having trouble reading a disc and moving the read head backwards to try to read the same spot again (& again & again …).

Whenever I need to clean an optical disc, I usually use warm water and dish soap. I've seen others talk about using isopropyl alcohol. Everyone seems to have a favorite cleaning methodology.