I have an ASUS Laptop and recently installed Ubuntu 16.04 LTS as dual-boot alongside my Windows 10. Grub and booting between those two worked without any issues. Today I started the Windows 10 Anniversary Update and hell began.
As you might know, after some time the update process enters the stage where the computer gets restarted several times. I left the laptop alone during the update, and when I came back the screen was just on and nothing was displayed. I left it for a long time until I got impatient and closed the lid: I expected just the screen to turn off, but instead when I re-opened it immediately after, a BSOD with Driver Power State Failure appeared (it was a new kind of Windows blue screen since it had a QR-Code on it; so probably from the update). It did a restart and instead of Grub the ASUS logo appeared. After some time the loading circle also appeared. But no hard-drive activity. I left it there for some time until I forced it to shut down and restarted it. In the past I once had this loading issue and a force shutdown and restart did it. But this time it did not help: after selecting Windows in Grub, the same thing happened: ASUS logo, loading circle, no hard-drive activity, forever... I did it several times, but no luck...
Then I tried booting into Ubuntu: it worked like a charm! While in Ubuntu I looked inside my Windows partition, but I could not find any of my personal files; only the Windows files and folders showed up. Luckily there was a
Windows.old folder where I could find my recent files.
The next thing I did in Ubuntu was installing Boot-repair and running it with the recommended settings (Paste-bin: http://paste2.org/tEH5bjBF). I restarted and now Grub showed me more Options for Windows:
Windows UEFI bootmgfw.efi
Windows Boot UEFI loader
Windows Boot Manager (on /dev/sda1)(this was previously the only one)
- And another Windows one containing something with "64" and "uefi" (sorry, I don't remember exactly)
But neither of them seemed to work. Each one of them showed the ASUS logo and then stuck there forever like I described above. Ubuntu still worked.
Then I went to another computer and created a bootable Windows 10 USB drive by downloading the Windows 10 ISO with the Media Creation Tool and then flashing it to a USB stick using rufus. I was hoping to being able to repair Windows by booting from the USB drive so I plugged it in, changed boot order in UEFI and restarted. Then again: ASUS logo, forever... I left it there for about 40(!) minutes and still nothing happened.
I then created a bootable Ubuntu USB drive and tried booting from it: it worked! I could try Ubuntu and everything worked.
What probably has happened to my Windows 10 during the update and what else can I do to successfully boot into Windows again? Usually the Automatic repair appears when something went wrong during an update, but in my case it sadly did not. And why the heck I can't boot from the Windows 10 USB drive?! My last hope was to completely reinstall Windows, but when I can't even boot from a Windows 10 USB drive I'm lost...