Will do then!
I'll create folders called
C:/Users/dcove/My Documents/My Games/Gas Powered Games/SupremeCommander/mods
and
C:/Users/dcove/My Documents/My Games/Gas Powered Games/SupremeCommander/maps
is that all I need? Should I attempt to put anything in those folders, or attempt a reinstall?

try running fa now

Eh? I don't have forged alliance.

Just for info, I left the folders empty, tried running it and got exactly the same fatal error (to be expected). Am I right in thinking that I need to copy some files into those folders, so that the game can access them from there, not wherever they currently are? If so, which ones?

Tis obvious reddev32 hasnt paid attention to what you needed help with.

He needs help with the Vanilla SupCom, not FA.

lol they both do the same think. I am running out of ideas now.

I tried again, this time copying all the map files into my artificial folder. Same error message.
I can't find any mods, so that folder is empty.

I take it we're fresh out of ideas?

Is there a way of just uninstalling the patch without uninstalling the whole game?

I think you're out of luck. While you can change where SupCom loads mods and maps, you can't change where it saves games and settings.

I think that's what's stopping you.

Okey dokey.

I really appreciate the help and the time taken! Thanks!

i would contect your companys it support and see if they have set permission on your desktop to block games and other services writing files to your docs folder.