Same problems here - was running the latest Avast free, and twice I tried to install the Windows 10 anniversary update, and twice it got stuck in a BSOD loop. So after finding this thread, I uninstalled Avast and then I was able to successfully install the Windows 10 anniversary update.
So, from what I am reading here, I am not game to try and reinstall Avast until there is a fix for it. Note I am running Windows 10 Home, 64 bit, on an Intel i7, 16GB RAM, Samsung SSD and Nvidia GTX 970.
Is there anyway to be notified if this issue is noted by Avast staff, and, when a fix is available? I am running Windows Defender, but to be honest, it isn't my preferred anti-virus. Would rather use Avast, when it is fixed.
Thanks.