www.makemkv.com

My ASUS BW-12B1ST f/w version 1.00 has been old-faithful through hundreds of DVD and Blu-ray disk mkv's.
However, once in a great while it spits out "No disc inserted" after attempting to scan a disc. Most recently, I tried to rip Blu-ray "Free Dance High Strung". The disc is brand new/spotless (no dust specks, nerfs etc but you know that, like quantum level stuff, just looking at it loaded crap onto it .
I checked my registered makeMKV v1.17.6 (latest update) Preferences->Protection : BD+ but the only switch is "Always create BD+ dumps". No other scan methods available.

I scanned these forums but couldn't spot a remedy.

Is there anything that I can do to make this disc visible to makeMKV or must I tag it as "No MKV"?

I bet that disc didn't mount in your operating system either. That implies that the failure is happening below the software level. If the optical drive can't find the disc, there's nothing MakeMKV or your operating system can do.

I have occasionally had to gently clean brand new discs. That might help here.

If your drive has been around a while, there's a possibility that the drive's optics could stand to be gently cleaned. I don't have any experience with cleaning drive optics, so perhaps others could comment.

Also, you could try it again. Given enough attempts, the drive might be able to finally 'see' the disc you put into it.

also on the first disc of the day always let the os see the disc first then open makemkv after that makemkv can stay open. But if you open makemkv first sometimes lg and asus drives get confused and hang have not seen it with official Pioneer UHD drives

There's something wrong with the disc.
There isn't a visible obstruction of any kind (fingerprint, scratch, dust etc) on it.
Still, I couldn't read it with Windows (11) Media Player either. (Haven't tried my Panasonic Blu-Ray disc player yet).
I inserted my 3M Scotch DVD Maintenance Kit DVD (it has 10 little "brooms") 3x into my PC's internal BD-RE ASUS BW-12B1ST drive, to clean the lens/LED. Still no joy. The next disc that I loaded presented no trouble at all. sigh.....