Unfortunately I did not realize that Bitlocker has to be disabled when creating a dual boot of Windows 10 + Ubuntu 18.04.
Therefore I currently find my Windows partition locked with Bitlocker.
Unfortunately I cannot access the Bitlocker recovery keys through my Microsoft account because they have never been uploaded to the cloud; never knew there was such thing as bitlocker on my comoputer.
How can I recover my Windows OS partition? Would I have to uninstall Grub? If so, would my Windows OS boot without problems? And afterwards, would my Ubuntu also still boot?