"Upgrading" to VMware Fusion 11.5.6 BREAKS virtual machines that worked with 11.5.5

[rdpiccard]

Something very like this appears from prior discussions to have been a problem for multiple people under circumstances that I could not identify.

I am using macOS 10.14.6 on a late 2015 27-inch iMac Retina 5K  - -  also known as iMac17,1.

I have four virtual machines:  Windows 8.1, Windows 10, macOS 10.13, and macOS 10.14.

All were working with Fusion 11.5.5, all are identically broken now that I have "upgraded" to 11.5.6.

When I try to start the virtual machine the following error dialogs are displayed:

1.  Could not open /dev/vmmon:  Broken pipe. (In a free-standing box on the same external monitor as the virtual machine library window.)

2.  Failed to initialize monitor device.  (In a drop-down box from the title-bar of the virtual machine's window on the iMac itself.)

3.  Transport (VMDB) error -14: Pipe connection has been broken.  (In a drop-down box from the title-bar of the virtual machine's window on the iMac itself.)

The TeamIdentifier hack discussed in the other thread did not make a difference.

Re-installing from a freshly downloaded copy of the installer .dmg did not make a difference.  It did NOT require me to re-enter the license key, so obviously it did not start by removing everything.  It gave me no choices about what to install or where.

[rdpiccard]

For clarification:  the working version, 11.5.5, was an upgrade from a prior version of 11.5 that was installed while still running macOS 10.4  - - I have no idea whether that matters, or not.

[ColoradoMarmot]

Try a clean install:

1) drag fusion to the trash

2) empty trash

3) reboot

4) empty trash

5) reinstall fusion

Then check system preferences/security for an 'allow' button.

[rdpiccard]

Did that.  Still broken.

After the reboot, there was nothing in the trash to empty; the fixed icon in the dock was still there; and when I launched the app, the license key was still in place. 

The system preferences - security&privacy shows VMware Fusion in two places (Accessibility and Full Disk Access), with the box already checked in each place.

NOT a "clean install" as I think of those words.  Is there some other way to de-install the product that really cleans it out while leaving the VM files themselves intact?

The problem behavior is identical.

Installing the update from 11.5.5 to 11.5.6 that was automatically presented to me by Fusion changed Fusion with four working VMs into a totally unusable state.