www.makemkv.com

I just bought a batch of brand new (wrapped) UHD disks (6) from a well known reputable retailer. None of the disks will open in makemkv. In makemkv, the icon shows the disk spinning and the "Type:" says loading... for about a minute or so, then stops. Then the "Type:" changes to No disc. There are no error messages. I've tried cleaning some of the disks but it didn't make any difference. I've rebooted my system twice. I've ripped over 600 disks to date with no issue till now. I'm on version v1.17.7 win(x64-release)

"Wrapped" means you're the first person to experience the problems with them. Often, new disks have a coating of, um, not sure what to call it, "chemicals" that obscure the content. This is especially true if they're older (6 or more months) after release. Sometimes, you'll see "sucker marks" on other parts of the packaging.

Have you cleaned them yet?

I suspect it's actually the drive as now, not even disks that I've ripped previously are working.
In answer to your question, yes, I have cleaned the disks. The disks are new releases.

Turns out it was the blue laser had failed in my UHD drive. Had to buy a new UHD drive.