2012 Macbook Pro. Fusion 10.1.6 was running fine under OSX 10.13.x, and I needed to upgrade to Mojave 10.14.6 for another program.
Then when I try to fire up Fusion virtual machine (XP or W10) I get that error message "Cannot find a valid peer process to connect to".
Tried uninstalling Fusion using the guide, and reinstalling it, tried later versions of Fusion - up to 11.5.7 - no joy.
Never see the message in Preferences/Security&Privacy about allowing Fusion.
Already verified Privacy/Security settings on MAC and "VMware Fusion" is allowed. Under General - allow App store and Identified Developers.
I am running in admin mode normally.
I have powered the computer off between uninstalls.
Have tried the suggestions here
Processes running are VMware Fusion Start Menu, VMware Fusion Networking, and VMware Fusion