AVG stalling on MacBook Air

Avg on my MacBook Air does not complete its scan and stalls or hangs at 67%.  it appears to be stop whilst scanning Macintosh HD, both AVG and the Mac are unto date with updates - any advice would be very welcome

Phil,
We apologize for the difficulties. In this case, we request you to uninstall http://support.avg.com/SupportArticleView?urlname=How-to-uninstall-AVG-AntiVirus-for-Mac and reinstall http://avgclick.me/1DNofWh your AVG. Once the installation gets completed, intiated the scan and check for the issue. If the issue persists, kindly attach us the screenshot of the scan interface. We will assist you further. Thank you!