Themes GUI Not opening

Hi folks, I occasionally search out new themes and icons for Cinnamon but today, after a day of not using my laptop, the Themes GUI doesn't open. It doesn't show any process on System Monitor. Not sure why this would suddenly happen and I restored a snapshot from 2 days ago using Timeshift but it didn't work. Any ideas on what it could be? I will most likely do a clean install of the new ISO (Victoria) when it releases so if I can't fix before then, so be it. Thanks.