The response from GOG Support:
Hello,
0) Please make sure that your Windows installation is most up to date.
1) Please open the GOG GALAXY App, select the game and use the repair button which will be located next to the PLAY button (on the right) > Manage installation > Repair
https://support.gog.com/hc/en-us/articles/360003930017-My-game-data-is-corrupt-How-can-I-repair-my-game-
2) Please install the June 2010 DirectX runtime package:
https://www.youtube.com/watch?v=1LL8Hna3FIc 3) If you are using Nahimic, please could you disable this audio software or uninstall it completely as it has proven to be problematic with many games? The article below might be helpful when it comes to disabling the Nahimic service:
https://support.gog.com/hc/en-us/articles/4408556606237 4) Please go to the game installation folder:- If the game was installed via GOG GALAXY, please select the game in GOG GALAXY, click on the icon on the right side of the PLAY button -> Manage Installation -> Show Folder- If the game was installed via offline installer, then you will have to manually navigate to the game installation folder, by default it's: C:\GOG Games\game-title\
Once in there find game's executable, right-click on it, and select Properties. In the properties window please switch to the Compatibility tab, and enable "Disable full screen optimization" and "Run as administrator". Press Ok to apply settings, and try to run the game again using the executable file. [url=https://support.gog.com/hc/article_attachments/360019085197/FullscreenOptimizations.gif(You]https://support.gog.com/hc/article_attachments/360019085197/FullscreenOptimizations.gif(You[/url] might want to close GOG GALAXY before performing this step).
5) Please close all software that has an overlay (this can include: Radeon Software, Rivatuner Statistics Server, MSI Afterburner, Discord, FRAPS, OBS, programs from Adobe Suite and similar software that may use overlay, or diagnostic tools).
6) Should the issues persist, please reinstall the game AND add it to your anti-virus/firewall software's exception/trusted list. Please make sure that you install the game to a short path, for example:C:\GOG or C:\Games