I actually troubleshooted an office I manage back in late December. I didn't check the MWB forum and today there is post about it on MYCE. I isolated it to windows 7, MWB 3 latest version. The temporary work around was disabling web protection. But I was able to reproduce the problem on demand. Please note that this does not happen on ANY of my Windows 10 machines, but this one office has chosen to stay with windows 7. These systems are nothing special, i7, i5 16gigs rigs. One with a realtek network and another intel. So with MWB fully enabled I was able to trigger the freeze running the speed test from www.dslreports.com. On one system running it from firefox would trigger it always. The other system running dslreports.com speed test from chrome would trigger it. Both systems were completely up to date windows 7 machines. One other thing to note, is that the lock up would happen during the upload testing phase of the speed test every time on both systems. Give it a try yourself. At least with this info you don't have to wait 5-20 minutes for it to reproduce. I was able to reproduce it right away each time on the problematic machines. For now the web protection is off.