As an Ubuntu + Win10 dual booter I had a couple of instances where Windows update destroyed things so irreparably that live Ubuntu boot-repair failed to work, and hours of back-and-forthing error messages to Ubuntu IRC and discord support channels yielded nothing. And I’m too stupid to know any other way of fixing it, so I was SOL. Your milage may vary.
As an Ubuntu + Win10 dual booter I had a couple of instances where Windows update destroyed things so irreparably that live Ubuntu boot-repair failed to work, and hours of back-and-forthing error messages to Ubuntu IRC and discord support channels yielded nothing. And I’m too stupid to know any other way of fixing it, so I was SOL. Your milage may vary.