Just installed Settlers 3 (with the newest patch (1.60)). When I started the game, it asked for a serial, which I found several topics here for.
First off: If I just normally start the game, as soon as I hit cancel on that box or I quit the game I get an "access denied" crash. This is easily fixed by running the game as an administrator, but my problems don't end here.

I read here that usually you just have to restart the game once for it to automatically set the serial. It doesn't do that for me at all. I can, however, use the serial that's on my GOG page and normally start and play the game. But, even then, it'll ask me for the serial (in all modes) again the next time I want to play.

Any idea what's causing this? I certainly don't want to have to enter a 20 digit serial every time I want to play.

I have the same problem.

Yeah I've just installed the game and it does it for me too.

So, I managed to partly fix this. What I did (not sure if all of this was necessary):
- Saw that some jumbled mess was set as "SerialNumber" in the registry, so I deleted that
- Ran "regs.cmd" (as administrator) again
- After this I could run s3.exe as administrator and it didn't ask for a serial anymore (doesn't work with s3_multi.exe and when run without administrator privileges)

Which means my only problem now is to get GOG to start this with administrator privileges from within the Galaxy client. Doesn't seem to help to set the Launch Settlers 3 link file to "run as administrator", so I guess I have to set something from within Galaxy?

It should be enough to rmb S3.exe ->properties and force in compability tab to run as administrator. It should run as admin even when you run it through gog galaxy or desktop shortcut.

Yeah, that's what I thought. But for some reason it doesn't work.

The error message I'm getting when not running the game as administrator is kinda weird, anyway.

It's showing an access violation at "E:\", which would be my CD drive (game is installed on D:\).

The hotfix that was just released for the game fixed my problem. Thank you!