[ton414]

The name of the game folder was changed by me.
You install first: HSFX 4.0, you run the file: HSFX_Version_4.EXE, you put the correct path.



My path is this: C:\Ubisoft\IL-2 Sturmovik 1946 HSFX
But this is your correct path: C:\Program Files\Ubisoft\IL-2 Sturmovik 1946.

Then you install HSFX 4.1: HSFX_Version_4_1.EXE.
You must ensure that files don't are corrupted.