Hi, all! I'm usually pretty good at fixing my own problems, but this one has so far resisted all my efforts.
TL;DR: The problem is that my Windows 10 install will no longer boot, and stops at the frowny face blue screen with the error "INACCESSIBLE BOOT DEVICE". Attempts to use bootrec /rebuilbcd find the Windows install, but result in an "The requested system device cannot be found" error.
Background: The desktop has been working fine all along. The major changes that may be related to this problem was the removal of several unused applications. They weren't getting in the way or causing problems, but in the interests of tidiness, I decided to uninstall the ones I no longer used. None of them are sketchy... it was stuff like Google Earth, OpenOffice, Sumatra PDF, GeForce Experience, some Steam games, etc. A few reboots were involved when a device driver was removed or changed.
Everything was fine until the final set of applications were removed, none involving device drivers. I don't remember what they were, since I didn't think it was remarkable. The next reboot was interrupted by an error that suggested the BCD was either missing or corrupted. Having dealt with this before (either when booting from improperly cloned drives or fixing other people's computers), I dug out my Windows 10 recovery USB, booted into troubleshooting mode and fired up the command line. But this time, the usual bootrec commands failed to work. Both bootrec /scanos and bootrec /rebuildbcd successfully locate the Windows installation (not at the correct drive letter, but I assume that's an artifact of booting into a recovery environment), but when I ask to add it to the boot list, I get the "The requested system device cannot be found" error.
I did a bit more Googling, tried a few different recommendations (including http://www.screwloose.com.au/windows-10-bootrec-the-requested-system-device-cannot-be-found which seemed to be the most promising), all to no avail. Mucking around in diskpart, I noticed all the hidden partitions on the boot drive were of type NTFS. I had read that one of them (maybe the one holding the boot records?) should be FAT32. I fired up my laptop, checked there, and sure enough there was a small hidden FAT32 partition there. I know FAT32 can be non-destructively converted to NTFS, but I don't know how that could have happened while uninstalling non-driver software.
Anyway, a lot more troubleshooting ensued (reformatting the hidden partition to FAT32, rebuilding the BCD entries from scratch, etc., etc.) but so far nothing has helped. I am at the point now where the Windows install itself seems to be fine, but for some reason the boot process cannot find it.
Other things I've tried changing, but did not have an effect:
- unplugging all other storage devices
- changing SATA settings from "IDE" to "AHCI" in the BIOS
- plugging the bootable USB key into a different port
- changing the "active" flag on the hidden partitions
- copying the /boot folder from one hidden partition to the other partitions (including the boot volume)
- running
bcdedit /store d:\boot\bcdto ensure that the file is readable and parseable (although I don't know if the entries themselves are correct)
I do not believe this was originally caused by the installation of new software or a Windows update. As I mentioned, the system rebooted fine a few times in the hour leading up to the emergence of this problem. I also do not think this is an issue with failing hardware. I have a USB drive dock that I've connected to my laptop so I can mount the desktop's drive there to have a look. It passes all diagnostics.
The nitty-gritty of the Windows 10 boot process has always been a bit of a black box to me, so I don't know exactly how it figures out where to find the OS to load. But the OS itself is still present on the drive, and I've been able to pull a few files off of it so I can continue working on my laptop. The bootrec command successfully identifies the Windows install, but for some reason is unable to record that information in the BCD. This is a very simple setup. One boot device, one OS, not even a second volume on the boot device. It seems like it should be fairly trivial for the Windows boot process to figure out what to do?
I can provide more details if necessary. Thanks!
Submitted April 23, 2018 at 11:19PM by Recyart https://ift.tt/2qRXXlR
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