id summary reporter owner description type status component version resolution keywords cc guest host 20319 Just installed v6.1.20's guest additions freezes Mac OS X El Capitan v10.11.6 guest VM & then host. Ant "Successfully (install/upgrad)ing VB v6.1.20's guests additions in Mac OS X El Capitan v10.11.6 VM cause a lock up to VM and then VB v6.1.20 in an old 2012 13"" MBP. https://forums.virtualbox.org/viewtopic.php?f=8&t=102608&p=498505 for my forum thread in details including logs. To make guest additions install/upgrade not freeze its VM and VB, disabling audio before starting up this VM prevents it. Thanks to fth0 for the answer." defect new other VirtualBox 6.1.20 other other