When using OpenSuse Leap as VirtualBox guest Os on windows host, OpenSuse regularly freezes (no more reaction to any gui), so that I have to shutdown/restart linux from VirtualBox.
I have noticed this on different hardware, possibly always Windows 10 Host. With OpenSuse Guest Additions or Oracle makes no difference.
As always…
Run monitoring apps on your HostOS to know how your subsystems, particularly disk are working.
Fully update everything, both Host and Guest
Consider what you’re doing in the Guest
Consider if you’re over-provisioning and are starving for resources
If you’re running any apps which have suspected memory leaks (eg FF over the years) then you can have resource starvation after long use
Certain non-default Guest settings will affect resource usage.
In other words,
Allocate resources smartly and make sure you have enough for whatever you’re doing
Start by analyzing on a conceptual basis (broad ideas), and gather performance metrics
If you think you have a real problem, then you need to gather what information you have, post that and describe what you might have done to analyze the problem.
In addition to what was said above, i remember something about some anti-virus messing with VirtualBox and its guest in a windows host. Sorry i can’t find the bug report now…