1)Open EF Launcher
2)Click OK on Error Message
3)Click on EF Settings Menu
4)Change the current path of CoH to the correct one. Currently you should have nothing, just a grey text box.
5)After chosing the correct path, you can now play from the launcher. Of course, perhaps you'll need to update your EF. If you updated EF before solving this error, most probably won't be able to update by the launcher, if not you should click on the "Check for Updates" button.
If you updated EF before solving this error, you should follow these steps:
1)Go to CoH folder, then to EF_Updates or something like that, you will recognize the correct folder because it stores the patches you download.
2)Execute each update in their respective order(Updates from 1.21 or above).
3)You are ready to play the lattest version of EF.
