Cannot launch Halo: CE on Steam; anti-cheat error

When launching the game I get through the intro splash then the game crashes. An error then displays:

Easy Anti-Cheat
Unknown file version (D:\Program Files\Steam\Steamapps\common\Halo The Master Chief Collection\haloreach\haloreach.dll).

I only purchased Halo: CE, I did not purchase Halo Reach. I have tried verifying game files and reinstalling. Neither has worked.

I had the same problem today. I had to uninstall and install the game to get it to work.

Hello guys!
A friend of mine just solve the problem:
Search on the Steam files EXACTLY for Halo1 (the last from the list on the Error window) and erase it.
That did it for me, seems pretty easy but spent a lot of time searching for the solution and never found it.
Hope it helps!