I have installed, started and played the base game which works perfectly.

When I install the DLC collection, the game won't start.

I have tried to use a 4gb patcher and that hoi3_tfh.exe that's linked on the mega thread paradox forum that's said to help.

I've went through the mega thread on HOI 3, nothing.

Twice I've tried to use the Verify & fix function in the Galaxy Launcher, but it doesn't work.

I've tried to delete the /map/cache files (not the folder), but that doesn't work either.

I've installed the Shark007 codec pack that the forum suggested.

The C++ Redistributables are re-installed/installed when I install the game with the Galaxy launcher.

I just don't know what to do anymore. I use windows 10 and the base game seems to work fine and I can play that.

When I use any .exe or launcher for the "Their Finest Hour" DLC, nothing happens. The mouse pointer shows something is loading, but then it stops and nothing happens.

I don't think the anti-virus is doing anything, because it would usually show me if it does anything to a game etc, and there appears to be no files missing.

I have since completely re-installed my windows 10.

I believe the problem may have been in the redistributables, as I had several of them installed from other games etc. Maybe a conflict somewhere.

But ultimately I can't really say, it's just speculation, as I have now re-installed the game and everything works perfectly.