I guess, I have tried: Sicherheits Update 2021-002 (Mojave) and Sicherheits Update 2020-007 (Mojave) The installation hangs after a while (now: for quite a long time: overnight ...): See Picture! I have tried to stop, restart the virtual machine, i have tried to mount the hdd-drive from the host OS, i have tried to add the hdd-drive to another virtual machine, nothing worked. Someone outside there: any idea?
I ran into this type of issue (different OS update), and had to resort to SafeMode on of OS-X. Even that failed to actually fix the problem. What I observed was that the OS was booting that it was hung on particular device drivers. Finally, after "Stop" I removed devices and continued to try. Eventually, it did finally boot, and then I added the devices back. From my memory, this finally enabled me to get the guest back working. A co-worker once asked me "Did you make a back-up", and my quick reply was "no". He laughed and said, it's always easier the second time. Which, IDK, likely not all that kind a joke in your predicament.
I have tried again to "stop" the machine, worked now. (I don't remember, that this worked last time). The I tried to start the machine in safe mode: Didn't work : lot of error messages ... The I started the machine from the recovery partition: Worked. I could not repair the hard drive, but before the next restart I added a 2nd hdd to the machine and could copy my data to this new hdd. Then I thought: Let's make a copy of the (although damaged) hdd to my NAS and there I found a copy of the virtual machine ... I "reactivated" this machine and dropped the old stuff. In german we say: Ende gut, alles gut ... Installing the updates worked this time.
