Occasionally in Windows 10 when a Blue Screen of Death (or “BSOD”) occurs similar to the above, the computer will not boot. The failure to boot can be caused by a variety of reasons. Many times it’s caused by the BCD/EFI store becoming corrupted (or by being “fixed” incorrectly by Windows particularly if you have a non-standard boot setup).
The following usually gets me up and running. Note that this post only applies to computers having UEFI firmware or using a UEFI emulator like the Clover boot manager or reFIND). Most computers built in the last 10 years use UEFI firmware.
Caution: Backup your hard drives before continuing. Although these commands typically do not cause data loss, it’s possible you have a non-standard configuration and/or defects on your drive. Not responsible for data loss – the following is at your own risk.
- Boot the machine from a USB Flash Drive using the Microsoft Windows Install Media USB drive. You’ll need at least an 8 GB flash drive.
- At the install screen below press the “SHIFT-F10” keys together to get a command prompt.
- The Recovery Console will open. Type the following commands:
- Find the volume that is FAT32, and has no label (or labeled “EFI” and is about 100 MB. It typically is also shown as “SYSTEM” or “Hidden” Here is mine as an example:
NOTE: If you do not see an EFI partition your computer is probably older and does not use UEFI firmware, using instead the older Master Boot Record (MBR) method of booting. If this is the case, then this post does not apply to you and won’t help you.
- Select that volume (in my example, Volume 2)
select volume 2
- Assign it a letter that is not being used by your other drives (I usually use A: as that is almost always available):
- Make sure from the list produced by the “list volume” command, that there is a letter assigned to the drive that contains your “Windows” folder. This is usually drive “C”. If the Windows drive is not assigned to C, or if “list volume” does not show a letter assigned to the drive containing your Windows folder, select the Windows volume and assign a letter to it as was done for the EFI volume above. In my example, I do not have to assign a letter since C is already assigned to the Windows drive.
- When you are done assigning letters to the volumes, exit diskpart:
- Use robocopy to make a backup of the files on your EFI partition in case something goes wrong. In this example I am copying all the files to my G drive, so substitute your backup drive letter for the “g” below. Robocopy automatically will create the “efi-backup” folder:
robocopy /COPYALL /DCOPY:T /z /e a:\ g:\efi-backup
- Before issuing the BCDBoot command, do a chkdsk on each of your EFI and Windows partitons to fix any errors (substituting the letters assigned to your EFI partition and windows partitions respectively for A and C below if yours are different):
chkdsk /f a:
chkdsk /f c:
- When those commands finish, issue the following bcdboot command which copies your system boot files into your EFI partition (substituting the letters assigned to your EFI partition and Windows partitions respectively for A and C below if your letter assignments are different):
bcdboot c:\windows /s a: /f UEFI
- Assuming the BCDBoot command was successful, reboot your computer and if you are lucky and the underlying problem that caused the BSOD has been fixed, rebooting will be successful. Note that on rebooting, Windows 10 often takes a while to reconfigure things or autorepairs after a BSOD and BCDboot command. You may get a few more BSODS and have to reboot 2 or three times before you get to the windows login screen.