I did a clean install of Catalina and then installed Fusion 11.5. When I try to run the Windows 7 VM, I get the following 3 errors. I uninstalled and reinstalled Fusion, rebooted the Mac, no change. What might I do to get this working/.
"Could not open /dev/vmmon: Broken pipe.
"Please make sure that the kernel module `vmmon' is loaded."
"Failed to initialize monitor device."
"Transport (VMDB) error -14: Pipe connection has been broken"
That did not help either. One thing I noticed the other day, maybe not relevant, is when I tried to import the VM, after navigating to the folder that contains the VM, was empty. I think I then used the open with command.
Solved. Since I use Voiceoer, I had missed the "VMware Fusion app was blocked" message in the Security preferences under the General tab.
This also solved the problem for me, although I don't use Voiceover -- I had just not checked the General tab.
I almost missed this solution though because it is not marked as an answer. (I think only the OP can do that.)