Who I have the same questioned this topic

I am struggling to get Message+ working on my Mac after changing phone numbers.

Message+ (M+) had been installed and was working on an old number.  I tried to disconnect my Mac using the application.  It offered a spinning wheel for several minutes before I did a Force Quit.  I uninstalled the application by moving it to the trash, rebooted the computer and reinstalled the application.

Interestingly, reinstalling the application allowed me to re-initialize the app to the new phone number.  I got the code and entered it and the application crashed.

In the meantime, I tried using the M+ web interface.  It operates pretty flaky, sometimes showing an active conversation and other times not, but that's not important.  Using the web interface I disconnected my Mac.

Now, the application will sort of start.  It shows cached conversations from the old number appear, and message box that says that the device has been disconnected and wants to know if I want to continue to browse message offline or Erase & Disconnect.  There's only one button, the latter.  So I press that button whose function would be fine with me.  But, then the app crashes again.

Now, I've tried to uninstall and reinstall the application.  But I'm no longer asked to reconnect with a new number.  

Somewhere on the computer is a cache of information that needs to be deleted but I'll be darned if I can find it.

Does *anyone* know where M+ caches it's data on a Mac or otherwise how to resolve this issue?  This is important to me because I'm switching to a Pixel device.  M+ is my only reasonable cross platform solution on the Mac.  Please help me!