When I installed this on my Win 10 work system, I went through the usual reboot and reloading the extension pack, then I tried to boot my Xubuntu 18.04 VM. It failed with this:
I thought maybe it was the VM itself, so I tried to boot my Xubuntu 16.04 VM and it failed the exact same way. (Yes, I use both and they were working fine on 5.2.22.)Failed to open a session for the virtual machine Xubuntu1804LTS.
The virtual machine 'Xubuntu1804LTS' has terminated unexpectedly during startup with exit code -1073741819 (0xc0000005). More details may be available in 'C:\Users\mrichter\VirtualBox VMs\Xubuntu1804LTS\Logs\VBoxHardening.log'.
Result Code: E_FAIL (0x80004005)
Component: MachineWrap
Interface: IMachine {5047460a-265d-4538-b23e-ddba5fb84976}
I figured it may have been a problem with not doing a full uninstall-reboot-reinstall, but I did that and it still failed to boot my VM. (I am not familiar enough with what VB does to make sense out of the hardening log.)
I uninstalled, rebooted and installed 5.2.24, which came up fine and works perfectly.
I also went back and repeated that same process (uninstall, reboot, install) with 6.0.2 - same errors again.
I'm back up on 5.24 with my VM running smoothly, and in the process I lost an hour and half of work time because of this.
I regret to say that I forgot to save the hardening log to be able to post it here. I can reproduce that at will if needed (and I recall to save the log). I can send what I have, but it only contains one error that I don't believe is the issue (there should have been at least two copies of the error, even though I got more than two total).
I suppose I have this expectation that a new release will actually work first time out when it's a major release upgrade.