No, I haven't either. It sounds like your experiences with Windows is very different from mine.Have you never open a document and it be blank, closed it and reopen for it to open fine, not corrupted but not read?
I would put "failure to read a CD or DVD" in an entirely different category.
Checking the license file probably takes a small fraction of a second when running UCCNC. If you are repeatedly seeing glitches in file reading, I'd suspect failing hardware. Windows 8.1 and 10 have been rock solid for me for the last 3+ years. And XP was as well before that.The software also checks for the license key every time, instead of just the once at install time. So this adds additional unnecessary complexity. The license text file is decrypted every single time, and compared against the statically (or dynamically) created key inside the software. All you need is a glitch in the reading of the file for it not to create the right match and throw an error.
Our $150K router at work is still running just fine on an 11 year old XP PC. No glitches there either.