Hi all, :o
I get this error sometimes when editing in MonoDevelop:
“Internal compiler error. See the console log for more information. output was: Unhandled Exception: System.UnauthorizedAccessException: Access to the path “C:\Users\Public\Documents\Unity Projects\State Machine\Temp\Assembly-CSharp.dll.mdb” is denied.”
After restarting Unity though, it works normally. It happens occasionally. Any idea what may have caused this? 
Cheers!
Can happen if your anti-virus software is busy analysing the file while the compiler wants to write to it.
I have the same exact error he is talking about, except it occurs VERY VERY frequently for me when im on my windows 7 desktop (doesnt seem to be a problem on my laptop idk why). It has nothing to do with my virus protection software, as it happens whether i have the software running or not (i turned it off to see if that was the problem). I never used to get this error before i reinstalled unity about a week ago (i had to do a clean reinstall of my OS because windows 7 was encountering problems). It seems to be a bug on Unity’s end, and i have absolutely no idea what causes it or how to fix it. 
No one else seems to know either