I also started experiencing this issue about 1 week ago. When I start Webex, it freezes as soon as it starts (I can see the attendee list). I cannot click anywhere on the application, and I cannot connect to audio. I need to use Windows Task Manager to end the application.
I also tried reinstalling, but this made no impact.
When I restart my machine, I can often times connect to webex the 1st time after restarting. I cannot connect a 2nd time.
I am not sure if this is related or not, but very recently I upgraded to Office 365. The issue was not present before this.