mscorlib.dll is an invalid CIL image
<p>I downloaded the new beta version of Unity (5.5.0b2) and when I open any project I always get an exception in the console that says:</p>

<blockquote>
  <p>The file C:\Program Files\Unity 5.5.0b2\Editor\Data\MonoBleedingEdge\lib/mscorlib.dll is an invalid CIL image</p>
</blockquote>

<p>I really don't have any clue to what this means and what to do about it, I can't even enter play mode, any advice on how to solve this?</p>

<p>I'm currently on Windows 7 64 bit, the Unity version installed is 64 bit, too, I tried installing it on the main hard drive and the secondary but the error is still there.</p>