Hi, all. So I am still on Mojave, and twice in the past couple of months, I’ve installed new versions of Parallels - the update from 15 to 16, and 16.1 to 16.1. In both cases, Parallels services wouldn’t run, and only reinstalling Mojave over the top of my current installation would fix it. (This was a known issue - Parallels had a knowledge base article for which reinstalling the OS was the last option.)
Turns out there’s a fix - and the same issue has been affecting VMWare, Karabiner, and other software that needs to install a kernel extension.
A recent version of Mojave has set permissions incorrectly for a temp directory used for staging kernel extensions, so their installation fails silently. I’ve written up the solution here:
In short: rather than reinstalling Mojave, you can boot into Recovery mode and run a couple of commands in the Terminal to set the appropriate flags on the directories in question. Only tricky bit was that, as I was running FileVault, my boot drive didn’t originally appear - I had to first run Disk Utility, mount it, and enter my password before the drive was visible on the command line.
Hope this helps someone!
—Michael