UnauthorizedAccessException during compilation

On almost ever c# class i create and edit it comes up the this error message.

Internal compiler error. See the console log for more information. output was:
Unhandled Exception: System.UnauthorizedAccessException: Access to the path “C:\Users\Public\Downloads\ProjectName\procedural\Temp\Assembly-CSharp.dll.mdb” is denied.

at System.IO.FileStream…ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] in :0

I am using version 4.3.3f1

MSDN describes the UnauthorizedAccessException exception:

The exception that is thrown when the operating system denies access because of an I/O error or a specific type of security error.

In a nutshell, Windows is preventing the compiler from reading your files. It’s not immediately clear to me why it’s doing that, but a quick search suggests your computer’s antivirus software might be the culprit:

just make a change to one of your scripts, a change that of course doesnt affect your script, like putting a space at the end of a line. then save the script and the error should go away. at least it does for me. ofcourse your mcafee real time scaning should be off.