Can not access Windows 10 after Ubuntu dual boot [duplicate]
Solution 1:
There are a couple of things you can try.
First of all, run sudo update-grub and restart your computer.
If you still can't boot into Windows, try out the tool boot-repair. You can install it in Ubuntu using the ppa mentioned in the second option. Run it, and it should bring back your Windows boot entry. If not, there is likely a problem with the Windows partitions.