Windows 10: Booting to black screen + blinking caret -- can't repair

"Running" Windows 10 (probably Pro, possibly N-edition) on a Macbook air 2012. Installed with Bootcamp Assistant which means a hybrid MBR, and legacy Bios mode for Windows (but not for macOS) on this particular model.

When booting Windows I just get a black screen with a blinking caret ('_'). It probably happened after a hard powercycle during an update.

Progression:

• Windows booted. No wireless networks listed. Turns out Windows' wireless service wasn't running and refused to start. I did a simple registry edit removing two out of three dependencies for that service. Didn't work, so I reversed my registry edit.
• I can't remember if I tried anything else. Anyway, I ended up in a never ending "Repairing Windows..." cycle, maybe because Windows got interrupted during boot by a hard power cycle.
• I could access the repair environment GUI but couldn't use any of the repair options. I tried them but they all complained that they were unable to do anything.
• After following previous guides here and trying some commands in the recovery console, I ended up booting to just a black screen with caret. Sometimes with a little mojibake (unreadable symbols) on the line above. This is where I am now, if we only look at the visual results of booting. I have done more troubleshooting described below...

I've made a Win 10 Pro 1903 install media on a 8 GB USB drive:

• None of the automatic repair options work when booting from it (legacy Bios mode USB boot).
• Sfc scans refuse to work and terminate immediately. No helpful error messages.
• Can't restore registry backup -- all files in backup directory have size of 0.
• Most commands can't identify the OS partition -- they say that there are 0 installed OSes.
• Checkdisk finds no faults with the drive. The drive is a year old Samsung SSD and macOS boots fine from it. The Windows partition can be read fine both from recovery console and from macOS. MacOS NTFS drivers do not complain about the partition or the file system. I am fairly confident the hardware and file system are intact.
• DISM command complains that the registry is damaged.
• DISM command complains that the scratch directory size might be insufficient. I don't know what that means exactly. Is the X: RAM drive too small? I don't know...
• DISM gives error 1009
• Bootrec runs /fixmbr and /fixboot successfully, but /scanos returns 0 identified Windows installations.

I feel like I have tried everything I could find in previous threads about the same issue.

I tried to list everything here, but I'm sure I forgot something, in which case I will edit it in.

No hardware peripherals except for the 8 GB bootable USB drive.

:)

 

Booting to black screen + blinking caret -- can't repair

"Running" Windows 10 (probably Pro, possibly N-edition) on a Macbook air 2012. Installed with Bootcamp Assistant which means a hybrid MBR, and legacy Bios mode for Windows (but not for macOS) on this particular model.

When booting Windows I just get a black screen with a blinking caret ('_'). It probably happened after a hard powercycle during an update.

Progression:

1. Windows booted. No wireless networks listed. Turns out Windows' wireless service wasn't running and refused to start. I did a simple registry edit removing two out of three dependencies for that service. Didn't work, so I reversed my registry edit.
2. I can't remember if I tried anything else. Anyway, I ended up in a never ending "Repairing Windows..." cycle, maybe because Windows got interrupted during boot by a hard power cycle.
3. I could access the repair environment GUI but couldn't use any of the repair options. I tried them but they all complained that they were unable to do anything.
4. After following previous guides here and trying some commands in the recovery console -- the last one being chkdsk /r, which I terminated prematurely since I didn't see the point of doing that on my SSD -- I ended up booting to just a black screen with caret. Sometimes with a little mojibake (unreadable symbols) on the line above. This is where I am now, if we only look at the visual results of booting. I have done more troubleshooting described below...

I've made a Win 10 Pro 1903 install media on a 8 GB USB drive:

• None of the automatic repair options work when booting from it (legacy Bios mode USB boot).
• Sfc scans refuse to work and terminate immediately. No helpful error messages.
• Can't restore registry backup -- all files in backup directory have size of 0.
• Most commands can't identify the OS partition -- they say that there are 0 installed OSes.
• Checkdisk finds no faults with the drive. The drive is a year old Samsung SSD and macOS boots fine from it. The Windows partition can be read fine both from recovery console and from macOS. MacOS NTFS drivers do not complain about the partition or the file system. I am fairly confident the hardware and file system are intact.
• DISM command complains that the registry is damaged.
• DISM command complains that the scratch directory size might be insufficient. I don't know what that means exactly. Is the X: RAM drive too small? I don't know...
• DISM gives error 1009
• Bootrec runs /fixmbr and /fixboot successfully, but /scanos returns 0 identified Windows installations.

I feel like I have tried everything I could find in previous threads about the same issue.

I tried to list everything here, but I'm sure I forgot something, in which case I will edit it in.

No hardware peripherals except for the 8 GB bootable USB drive.

 

Booting to black screen + blinking caret -- can't repair

Download and install Windows support software on your Mac - Apple Support
Boot Camp - Install and use Windows on your Mac.
Blinking Cursor when booting Windows 10 o… - Apple Community
Bootcamp boot -> black screen Blink … - Apple Community

These are a start for you to understand that you are going to have to look at this as if it was a problem with something inside of Mac OS not the other way around which it is a Mac hardware problem with Windows 10. Again why I do not mix the two together. Otherwise you end up up a huge Migraine.

 

Booting to black screen + blinking caret -- can't repair

Hi,

- do you mean a hyphen or underscore? - a caret is ^

Perhaps your best hope is that your boot priority has somehow changed and your PC is trying to boot from another device. That seems something you've not checked, noting you've been quite thorough.

However, that's an outside possibility, I'd guess, given the other evidence.

Indicative of the system not finding a valid bootable medium, of course.

- clearly signicant and would argue against trying to recover your Windows partition alone.

I discovered MS disabled this feature around the end of 1709 -> 1803.

You can find articles about this now, cited on tenforums, where MS argues it saves space. Hmm.

I assume you haven't yet discovered the value of using disk imaging routinely- so frequently recommended on tenforums- e.g. Macrium Reflect (free/paid). If you had a disk image you could have restored that and be up and running, hopefully.

I think you're looking at doing a clean install.