Happened to me today as well. I have no antivirus and I'm pretty sure that I don't have viruses(trust me :music_whistling:). Last modification date for this file (dcs.exe in my case) is the same as last update - June 24, and I'm sure I've played since then and it was ok. In file properties I've noticed that it has signature verification problems. The only possible explanation was that they signed new dcs.exe file with some new certificate or my certificate become out of date. In windows update I've noticed that I have 14 pending updates. I've installed those, rebooted and everything worked. Check if you have pending updates in Windows Update and install them.