I have the latest Grayface patch installed, running in compatibility mode/16bit etc; still having the alt-tab issues but I can live with that. Can't live without the game saving, though; anybody got ideas on that?

As a general rule, you should provide more information about your system (hardware, OS, etc.) in order to get help.

Anyway I have a question: what directory you installed the game into?

Good points all around!

OS: Win10
CPU: Ryzen 3600
GPU: 1660 Super
RAM: 32GB 3200

Installed as default per GOG Galaxy, which has it in Program Files (x86). I've tried setting compatibility differently to see if that works but no joy there, which has about exhausted my meagre troubleshooting abilities.

I think this happened to me once trying to edit saves which made them open with a different program by default (yeah I'm stupid), if this is the issue its a fairly easy fix you can google.

You might need to install outside Program Files. Try making a "games" directory under the C drive or something and install your games there.

I suspected that you installed the game into "Program Files" because the issue is probably related to permissions. As Bookwyrm627 correctly suggested, you may want to install the game into a different, unprotected directory.

Thanks for the suggestions, folks! I've installed to a directory outside Program Files, verified, run as administrator, tried to troubleshoot compatibility, and still no luck. When I try to test it after adjusting compatibility it tells me there are missing files, but a reinstall and verification doesn't fix this. I can launch it without adjusting compatibility just fine and load autosaves etc, but saving still crashes the game.

Reinstalling it with antivirus temporarily off fixed the save issue, and now I feel silly for not trying that earlier. However, if I try to run it in compatibility mode it still gives me the missing file error. So far doesn't seem to have any issue if I launch it as-is direct from the folder or GOG/start menu. Thanks everyone for your patience and help!

I'm glad you got it solved. Please mark the relevant post as the solution so others later can quickly jump to the post that finally fixed it for you.

Done! Didn't realise that was a thing, thanks for pointing it out :)

I'm glad of having helped you. Enjoy the game.

I wonder if the "missing file" is something to do with (one version or another of) DirectX? I do not understand what went on with that between different versions of Windows, I only know that something did. And that there is (or at least was) something to download from Microsoft: directx_june2010_redist. I needed it to fix a problem with another game's sound.

That's very interesting to hear, I may have to do some experimentation with that in the future. Thanks for the note!