For those of you on the latest version of Windows 10 Technical Preview (build 9879), there is a new tweak available that allows you to turn that search icon on the taskbar into a useful search box. This feature is disabled by default but you can unlock it with a registry tweak.
Now, keep in mind that you are messing with the registry, so make sure you follow the example bellow. Once you are done, you can right click on the taskbar and show the search box, the search icon, or disable the search button completely. Here are the steps:
- Open Registry Editor.
- Go to the following Registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Search
- Create a new DWORD value named EnableSearchBox and set it to 1. If you already have this value, then just modify its value data from 0 to 1.
- Sign out and log in back to your Windows account. Alternatively, you can just restart the Explorer shell.
- Now, you will see a new Search box in the taskbar of Windows 10!
Further reading: Microsoft, Windows 10