P: Hanging on launch (Mac 10.14.6)

A Preference File will survive a Lightroom uninstall/reinstall. Sometimes weird behavior is corrected/cured by resetting the preferences. 

Reset Procedure:1. Close Lightroom.
2. Hold down [Alt/Opt]+[Shift] while restarting Lightroom. 
3. Overwrite the Preferences when prompted by the dialog.
4. Close Lightroom.
5. Restart Lightroom.
Does the behavior continue after resetting the preferences?

I followed your instructions but I am still getting the same issue.  Any suggestions?  Thanks

This sounds like a bad install. Reverting to 8.3.1 likely cured the bad install.  You should attempt to reinstall again.

Clean Classic Install ProcedureClose Lightroom
Restart the computer
Use the Adobe Creative Cloud App to uninstall Lightroom Classic
Restart the computer
Install Lightroom Classic via the Creative Cloud App without launching any other programs.
Restart the computer
Launch Lightroom
Wait 5 minutes

have you tried using opt/alt when starting up LR to choose/create a new catalog?

and I restarted after the install.

Here is the info for my Mac:

hmm, could be a GPU issue... which mac and video card do you have?  Did you restart after the install?

It is unresponsive and does not open.  Screen shot of activity monitor is below

Hangs, how?