Search Box is missing
In Start Menu:
In Windows Explorer :
Open Control Panel > Programs and Features > Turn Windows Features on or off.
Check ‘Windows Search’ to get it back. To disable Windows Search, uncheck the option. Click OK and for Windows to configure the settings. Restart your computer. TIP: See this post if the Windows 10 Search bar is missing.
Disable Windows Search
Using Windows Registry Alternatively or additionally, you may also have to check if this registry key exists. Open Registry Editor and navigate to the following registry key: If a value called NoFind exists in the right pane, delete it. A value 1 would mean that search and the following features have been disabled:
The Search item is removed from the Start menu, and the right-click context menu.The system does not respond when users press F3 or Win+FThe search item does not appear in the drive or folder right click context menu.The search item may appear on the Standard Buttons toolbar, but Windows will not respond when you press CTRL+F.
If the key does not exist or has a value 0 then it is the default state; i.e., Search is enabled. Exit regedit. It is always a good idea to back up the registry or create a system restore point first before touching the Windows Registry.
Using Group Policy Editor
You can also open Group Policy Editor and navigate to: Ensure that Remove Search link from Start Menu is Disabled or Not Configured. This should help. If you turn off Windows Search the following things could happen: Check this post if Help window keeps opening automatically. Also, see: