This will disable web search in the Start menu for Windows 10.

1. Open regedit

2. Navigate to HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Windows

3. Either navigate to or create the "Explorer" key under the "Windows" key.

4. Create another DWORD (32-bit) value called "DisableSearchBoxSuggestions".

5. Set this new entry's value to 1.

6. Close the registry editor and re-login or restart.