Posted May 29, 2023
James_Neave: I found a solution to this here:
https://support.gog.com/hc/en-us/articles/213520069-Settlers-3-Ultimate-Collection?product=gog
Under "Settlers® 3: Ultimate Collection - Game asks for CD-Key in singleplayer mode"
If you are using GOG GALAXY, select the game and click the customization icon (next to PLAY):
→Manage installation
→Verify/Repair
This fixed the CD key issue for me after I had fixed the not-starting issue by using the offline installer
How do you download the oofline version?https://support.gog.com/hc/en-us/articles/213520069-Settlers-3-Ultimate-Collection?product=gog
Under "Settlers® 3: Ultimate Collection - Game asks for CD-Key in singleplayer mode"
If you are using GOG GALAXY, select the game and click the customization icon (next to PLAY):
→Manage installation
→Verify/Repair
This fixed the CD key issue for me after I had fixed the not-starting issue by using the offline installer