After upgrading to 10049 I have had a lot of problems but this is the weirdest one. Typing to the searchbox is disabled. It shows search on Web and Windows but when you click it is unresponsive. I cannot type anything. It doesn't disappear as well.
I had a similar issue as well when I first installed. I also had internet ip address issue at the same time. After I was able to repair my internet connection the search box would work again. Seems you need the internet connection for it to work. Hope that helps. Update...I just noticed mine is not working as well. It was working but now its not weird.
If I hadn't had an internet connection, I would have posted this message This is really weird. All happened after I ran sfc /scannow Are you on VM as me? How had you fixed?