title: File Load Some bytes have been replaced with the Unicode substitution character while loading file
body: <p>I was debugging in the .Net framework source code suddenly when I stepped into a file of theirs, visual studio 2010 raised this error:</p>
  <blockquote>
  <p>File Load:<br />
  Some bytes have been replaced with the Unicode substitution character while loading file XXX, Saving the file will not preserve the original file contents.</p>
  </blockquote>
  <p>when I click OK, the file is marked as unsaved, and when I try to save it, it says that the file is locked, but I can overwrite the file. I don't know what this message means.</p>
  <p>And why is now, not the first time when visual studio downloaded the file from the Symbol server?</p>