@mike-o Not sure, but some thoughts.
You said that trying to open launcher.exe directly gave the error. Since Opera's shortcuts typically load launcher.exe, it probably doesn't have anything to do with shortcuts in general and something to do with launcher.exe. You might have even been able to create a shortcut named "My Test Shortcut" (anything that doesn't have "Opera" in it where Opera might fix the shortcut on you to change it to load launcher.exe instead) and have it load opera.exe instead (since you said loading opera.exe worked).
As to why it works on a different drive, not sure. It could be some security software that doesn't like launcher.exe on the main drive.
launcher.exe could have been corrupted and uninstalling Opera and deleting the install folder that remains before reinstalling might have somehow made a difference.
It could be something limited to your user account. If you created a new Windows user account (local only not tied to a Microsoft account), and tested Opera there installed on your main drive, it might work. Then, you'd have to figure out what's wrong with your normal account of course.
You might want to try https://crystalmark.info/en/software/crystaldiskinfo/ to check the health of your SSD.
You might want to scan for malware with the free version of Malwarebytes just for good measure.
You might want to check your system files.
You might want to check the filesystem on the SSD. See the "How to Run CHKDSK With the Right Flags" section at https://www.makeuseof.com/tag/stuck-chkdsk-use-fix-right-way/ for SSD-specific instructions. launcher.exe could keep ending up in a spot on the file system/disk that is corrupted.
You can make a test standalone installation of Opera to a folder on your desktop and test if its launcher.exe has a problem. If so, you can try to figure out how to fix the issue without messing with your normal Opera on the other drive that works.
