For some reason you might find that you can't boot into Windows.
If this happens, you may need to re-write the Windows System partition. Here's how to do it.
*** WARNING use these steps at your own risk ***
*** These steps may irreversibly damage your computer ***
Try https://www.thewindowsclub.com/rebuild-bcd-windows-10 first.
Otherwise below are the manual steps for advanced users.
Get into the WIndows Recovery Environment:
2. Choose Troubleshoot > Command Prompt.
3. If you have Bitlocker, enter your Bitlocker Recovery Key.
4. In command prompt, try typing:
c:
dir
5. If you recognise the contents (it should have a Windows directory there) then this is your hard drive.
6. Type the following:
diskpart
list disk
7. Take a note of the disks available. If there is more than 1 disk, check the disk space size. Or power off your computer and disconnect all other disks apart from the disk that you know contains your hard drive then start from step 1 again.
8. Type the following (where X is the number of your disk):
select disk X
list partition
9. Take a note of the partition that is called "System".
10. Type the following (where Y is the number of the System partition):
select partition Y
assign letter = S
exit
11. Now type the following command to restore the default boot partition:
bcdboot c:\windows /s S: /f UEFI