the logs aren't any good in this case, as its the drivers that are crashing, theres no info in those logs for that, ngtool installs and the service works fine, untill, you run software in the vm, you sometimes get a disconnect or a connect sound (sometimes not) then I get blue screen, in other cases it works fine, its got to be unstable avast driver not virtualbox. You also removed the reboot after install of avast over the top(updating/upgfrading), when it needs a reboot to appl the firewall driver, and having avast run ngtool before the avast software is even ready is silly also. I me here waiting for ngtool to finish so I can reboot to apply the firewall driver, if I just reboot, I get half a virtual machine and ngtool doesn't kickin to reinstall. Never had issues with any of the previous betas like im having with the 2 latest releases.Somethings changed for the worse.