title: Visual Studio pre-build scripts can't find exe files in windows/system32
body: <p>I'm stumped. All of a sudden Visual Studio cannot find exe files in the Windows/System32 directory (such as <em>xcopy</em>, <em>attrib</em> etc).</p>
  
  <p>I have some pre-build and post-build events that execute batch files that use xcopy and attrib. Previously they were working fine but today, during the build process, Visual Studio cannot find them. The error is shown: <em>'xcopy' is not recognized as an internal or external command, operable program or batch file</em>.</p>
  
  <p>When I first noticed the problem I tried running xcopy in a regular cmd prompt and the same problem occurred. After I restarted my computer, the problem disappeared in the regular cmd prompt but remained in Visual Studio. After the reboot, the problem does not occur in the Visual Studio cmd prompt either - only from within Visual Studio itself.</p>
  
  <p>Everything appears normal if within one of the batch files I execute <em>set</em> to check the PATH variable or <em>echo %systemroot%</em>.</p>
  
  <p>In the Tools->Options menu there are settings for VisualC++ directories. However I am running C#, not C++, and besides, I never changed these settings and they appear to be correct.</p>
  
  <p>Anyone had this problem before? Thoughts?</p>