Same, luckily I was able to roll back to 11.5.3 using Time Machine but what kind of shoddy planning is that? No self-respecting software company unsupports an OS halfway through a release cycle. If a necessary change to the app warranted cutting off High Sierra then it needs to wait until v12. And if the OS is not supported then it should not install.
That's enough to make me consider switching to Parallels (and I've been on Fusion since v1.0).
I'm running macOS Catalina 10.15.5 -- just upgraded to VMware Fusion 11.5.5 -- completely broke every VM. Fusion is totally unusable now. I made zero changes, just installed the upgrade and booted, immediately after login, VM either hangs or takes no input from keyboard, mouse, or touchpad (hard to tell). While I can still use the Fusion menu in the macOS host, the guest OS cannot be interacted with at all.
From the other posts starting to emerge in this forum, it appears that something significant was changed in this upgrade, and perhaps a little bit over-ambitious attempt at progress might have broken Fusion in more than one use-case.
Let's hope a quick fix is forthcoming. I may try to downgrade if possible.
Unfortunately, a complete uninstall of 11.5.5 and new installation to 11.5.3 didn't help. I'm now completely without VMware Fusion. Help....thx.