Customize/Live Preview not working

Based on looking at Firebug, I’m not sure I would have any idea what to do with it.

Strange. Even though the problem was happening in both Firefox and Chrome, which led me to believe it was not a browser problem, Firefox had been running very slowly recently, even stalling, so I uninstalled it and reinstalled it.
At first Firefox acted better, but after re-loading my saved settings from the previous install of FF, it started to stall again. Btw, still no change with customize/live preview.
I looked into troubleshooting FF and went to Help> Troubleshooting Information > Reset Firefox button.
After that it restarted and – lo and behold – customization/live preview works!
I still don’t understand how something that was going on with FF could affect Chrome, but now that I think about it, FF and Chrome were always running simultaneously (I think)… I don’t get it, don’t really know if that was what fixed it, but I’m happy it’s working again & hopefully it will continue to work.

Thanks again for your help, Fee

I’m happy you solved it ??

I am having the same problem across multiple domains, hosted at Fat Cow.

I use one domain as a test site only, so today, I reinstalled WP3.5.1. and deactived all plugins. It defaulted back to Theme 2012, but I still cannot preview it, or any other themes. The preview box is simply blank. Since it is happening across multiple domains, I contacted my hosting company, they poked around, and said it must be an issue with WP, not a server problem. This is very frustrating, as I am looking to change themes on one of my live sites, but without preview and the ability to change the theme options I cannot move forward.

@vprehn – if you need help, you need to start your own thread. This one is outdated, and despite any similarities, it’s unlikely your issue is the same.