The 3603 beta patcher can't recognize it, either. Replays from my Steam version are listed in the replays menu but can't be played.
It might be a bit late, but I got the patcher working on the GOG version. It can be done by doing the following steps:
- Install or copy the game files under the following path: C:\Program Files\THQ\Gas Powered Games\Supreme Commander - Forged Alliance\
- Rename bin\SupremeCommander.exe
- Copy the patcher to the bin
folder and run it.
- The initial process will fail, so uncheck the Safe Mode checkbox and press Start.
- It will still say it failed, but it will actually update the EXE.
- Rename bin\ForgedAlliance.exe
back to bin\SupremeCommander.exe
- The main menu now should have the 3603 version number in the top right corner.
I didn't do any significant testing, but the game and the campaign launches fine. I did this on a permanently offline rig, so I believe the patched EXE is still DRM-free.
Compared to the Steam version now the only differences are the EXE (obviously) and lua.scd
. I diff'd the LUA files and all the differences seem to be related directly to Steam or the multiplayer lobby in general, neither should really matter for solo or LAN.