I faced this issue as well and figured it was my configuration that was faulty, although it appears as it's just a defect of a new feature and also present in the retail ISO. It maybe isn't the case for this thread but in my scenario it appears as Microsoft changed Windows WSearch service startup mode to Automatic (Delayed Start). This prompts the search to show a poor animation and a blank page with absolutely no results when you try to search just after a fresh installation.
In my case, rebooting the computer and waiting a couple of minutes solves it (slow HDD). I suppose the indexing service has to seed its database before it can output any results, delayed startup in turn can be beneficial to performance once the database exists in the longer run, it's just merely my speculations though.