Installation of LR 6 on a second (laptop) computer to make it wearable did not work, the the installer claimed to be fake. Why it is from my CD copied to an USB memeory since the laptop do not have a CD reader.
So not Catalina or Big Sur. You would not be able to install LR6 on those MACOS as the installer is 32bit, and those MACOS absolutely prohibit that. Despite LR 6 being 64 bit.
Suspect a protected hidden file exists on the original CD media you cannot copy to a thumb drive.
You might want to invest in a cheap external CD, or better BlueRay DVD drive (USB). But be prepared to be disappointed. Above is an assumption.
This CD, it came in proper Adobe box?
Used to be a lot of gray market privacy on the market.
Also, now this is a long shot.
If I remember correctly, with v6, an option to register the software at adobe existed. And this would allow you to download the program and view license at Adobe. Few may have accomplished that. And Adobe may have removed the download, and may no longer list the license.
That at adobe.com , sign in, manage account, and I forget the rest.