Solution to the Error code: 0xc0000225 in Windows 10.

1. Type in 'Diskpart'. 
2. Type in 'List volume'. 
3. Type 'Select volume=?' (Replacing the ? with whatever number is associated with the ESP label). 
4. Type 'Assign letter=Z'. (Or anything not currently in use.) 
5. Type 'exit'. 
6. Type 'bcdboot C:\windows /s Z: /f UEFI'. (Replacing the C: with the volume letter that is named OS).