1. Quit out of your Topaz Studio 2 installer.
2. Open a new Finder window
3. Hit CMD + SHIFT + G to open the Go To panel
4. Enter the path ~/Library/Preferences/ into the input field
You should see a large number of .plist files in that location
5. Type Studio in the Search box on the top right-hand side:
6. Click the Preferences button so that you are only searching the Preferences folder
7. Right-click the com.topazlabs.Topaz Studio 2.plist file and select "Move to Trash"
8. Run your Topaz Studio 2 installer again.