Unable to boot Windows 10 after update

Question

Of course, a while back when searching for something unrelated, I came across a question almost identical to mine, but can't find it now.

Since turning off and restarting my computer a few days ago, I haven't been able to boot into Windows. My suspicion is that it's related to an update Windows had a couple weeks ago; after the update, I hadn't booted into Ubuntu until just the other day, and upon restarting and trying to start Windows, GRUB just gave an error message(I don't recall the wording, but something about Windows Boot Manager not being found/available) and prompted me to try again. Tried this a few times with same results. From Ubuntu, I tried installing and running boot-repair, but all it seemed to do was cause my computer to skip the GRUB screen entirely and boot straight into Ubuntu. Here is the pastebin link given by boot-repair:

https://paste.ubuntu.com/p/HyJyTvnDn9/

Any help is greatly appreciated.

Answer 1

Your computer's hard drive is a GPT disk as expected. Enter the UEFI setup utility and disable the Secure Boot option which may have been enabled by the latest Windows 10 update. If that doesn't work try using Rescatux to fix it.

Rescatux is a free bootable live CD/USB that can repair GRUB and the Windows bootloader. Rescatux has a graphical interface with a menu of operating system rescue tasks. If your computer has UEFI firmware, you can select among the UEFI boot options.

Boot options:

• (>=0.41 beta 1) Update UEFI order
• (>=0.41 beta 1) Create a new UEFI Boot entry
• (>=0.41 beta 1) UEFI Partition Status
• (>=0.41 beta 1) Fake Microsoft Windows UEFI
• (>=0.41 beta 1) Hide Microsoft Windows UEFI
• (>=0.41 beta 1) Reinstall Microsoft Windows EFI
• (>=0.41 beta 1) Check UEFI Boot

GRUB options:

• (>=0.40 beta 11) Easy GNU/Linux Boot Fix
• Restore GRUB and GRUB2
• (>=0.31 beta 4) Update any GRUB2 menu
• Update Debian/Ubuntu GRUB menus

Windows options:

• Restore Windows MBR (BETA)
• Clear Windows passwords
• (>=0.31 beta 4) Promote a Windows user to Administrator role
• (>=0.41 beta 1) Reinstall Microsoft Windows EFI
• (>=0.31 beta 4) Unlock Windows user

Password options:

• Change GNU/Linux Password
• Regenerate sudoers file
• Clear Windows passwords

Expert tools:

• Boot-Repair
• GParted
• OS-Uninstaller
• Clean-Ubiquity
• PhotoRec
• TestDisk

^{Rescapp is a nice wizard that will guide you through your rescue tasks.}

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How to make a Rescatux live USB from Ubuntu

1. Insert a USB flash drive and check if the boot flag has been enabled on the flash drive using the GParted application. Unmount the USB flash drive. Open GParted and select the USB flash drive from the menu list of drives. From the GParted menu select: Partition -> Manage Flags -> check boot.

2. It is very important to verify that the device that you are installing the Rescatux live USB to is indeed your flash drive, so that you don't overwrite any of your system or personal files which may make your operating system unbootable. In Ubuntu you can find the device name of the flash drive using the Disks application.

3. Unmount the USB partition device. Let's say the USB partition device is /dev/sdc1

   sudo umount /dev/sdc1 # replace sdc1 with the partition name of your USB drive
   

4. Change directories using cd to the path of the directory where the Rescatux iso file that you downloaded is located.

5. Write the Rescatux iso file to the USB flash drive. In the following command replace rescatux_0.xxxx.iso with the name of the Rescatux iso file you downloaded.

   sudo dd if=rescatux_0.xxxx.iso of=/dev/sdc # this command also works in Windows Subsystem for Linux version 2  
   sudo sync  
   

I have also been able to make a Rescatux live USB using the built-in Startup Disk Creator app.