A conflict with the McAfee antivirus has been noticed, this is a "false positive" which causes some EXE files to be deleted from the game's folders.

-Open McAfee and restore quarantined files (if they have not been deleted)
-Parameter an exception on these files (see the McAfee user manual)
-Relay the game


-Make McAfee in "pause" mode or temporarily close it
-Start a file check by the Steam tool (the deleted files will be restored)
-Relay the game