Dear Mr Agent, freeze makes screenshot impossible... System hangs at end of install. Can move mouse, drag the installer window (but it leaves trails). ctrl-alt-del brings up expected dialogue box, but task manager won't start. Alternatively, a shutdown and reboot (instead of task manager) hangs. Hard reset only way out. Been like this for me since build 5.0.314 or the previous beta, if I recall correctly. No other AV, uninstalled, rebooted, new Avast removal utility run, rebooted, and then installed, so all was clean.
Getting a bit tired of reporting this over and over with no resolution, to be honest.