I just got my backup copy of The Witcher from GOG and for some reason, it is looking for a disk when launched. I can bypass the error, it doesn't matter which option I choose (Cancel, Try again or Continue), the game will still launch, but it is rather annoying that it keeps happening every time I launch it. I did have my original purchase installed before installing the GOG download, but that was not a disk version (digital download purchased from the Atari store) and I did uninstall it before running the GOG installer. Anybody got any ideas on this one?

Yes, as I said in my original post, I did uninstall the old version before installing the GOG version. However, the old version was not a disk based anyway, so I don't see how it could be the cause. It's actually the executable, not the launcher, that is producing the error, so it doesn't matter how I run it, the error will always happen.

EDIT - Well, it appears I managed to solve it on my own. I uninstalled my old anti-virus (Avast Free) to try something different (MSE) and now the problem doesn't happen at all. Chalk it up to one of those weird interactions between anti-virus and other applications.

EDIT 2 - Can't credit myself with a solution, so the only responder gets the credit, just so this thread can be marked as solved.