Hello,

   Every time I shut bitcoin core down and try to restart I get:

"A fatal error occurred. Bitcoin can no longer continue safely and will quit."

EXCEPTION: N5boost12interprocess22interprocess_exceptionE
Access is denied.
C:\Program Files\Bitcoin-qt.exe in Runaaway exception.

I save my wallet, download the software and reinstall it starts up again downloads the block chain, I have tried putting the block chain in the directory from the torrent file and first start up fine, but if I try to shut down and re start I get the error.  Please let me know what I am doing wrong or how to fix it, please dumb it down I am a beginner at this.

Thanks