If an upgrade has resulted in a broken install, uninstall Geneious and delete the Geneious application folder (not the Geneious Data folder, eg"Geneious Prime Data" or "Geneious 9.1 Data"), then reinstall Geneious. If this does not fix the problem, there are two other options you can try:
1. On a Mac, when you upgrade your memory gets reset to the default (this is due to how up-grades are handled on the Mac). Sometimes, if you have very large files in your local database, the default memory won’t be sufficient to handle these files. To fix this, find the Info.plist file which is in the Geneious.app folder (right click to Show Package Contents and browse into the Contents and you’ll find the file). Open this file in a text editor and look for the VMOptions key. Edit the -Xmx value increasing the memory allocated to your previous value which worked. Save and close the file, and start Geneious again.
2. There have also been some issues with the user preferences.xml file found in your Geneious Data folder which can be solved by renaming the file so Geneious creates a new one. If this wasn’t the problem, you can rename it back without having lost all your preferences unnecessarily.