We need more information. For example, what steam button?

Hi All, I'm having a similar error, I purchase the Western Sahara DLC and it was working fine, but this week it beginin to give a "file not found" error even though the file was in the folder, I've completely reinstalled the game three times and recreated the file air_f_lxws.ebo that has a problem but always gives the same error. Can anybody help me too?

Did you already try to verify game file integrity via Steam? If yes and the issue still happens, try downloading the compatibility data from the workshop as a temporary workaround: https://steamcommunity.com/sharedfiles/filedetails/?id=2636962953