So it all started when I took out my system disk and stuck it in another computer (windows 7) to access files. I used the windows 7 os for everything, and on one boot it ran chkdisk on my windows 10 hard drive. When I put the Win 10 hard drive back in my original computer, it bsod'd on boot with the error (ntfs_file_system). I then tried the "automatic repair" option from the windows 10 boot menu, but that only made matters worse, changing the bsod message to (bad_system_config).

I tried booting to a windows 7 install on the same computer, and it couldn't get into the filesystem of my windows 10 drive, saying access is denied (though i could before this mess started)

I ran checkdisk again, this time from windows 7. Maybe this fixed the file system, who knows, but i still can't get aroud the bad_system_config bsod. I still can't access the files from windows 7.

Safe mode doesn't work either. I had a restore point, but for some reason windows doesn't find it... (maybe cause the file system is messed up)

should i just choose the "reset windows" option? will it keep my files even in this state? preferably, is there another way to fix it...

Update: bootrec /fixboot and bootrec /fixmbr have not helped

running chkdisk from within windows 10 cmd prompt has not helped

awesome news: while windows 7 can't see the filesystem, it is still accessible from linux, so I can copy off all my files to then reinstall windows.

final update: I resorted to reinstalling windows. Took 7 hours to set my computer back up how it used to be, but all is good now. Just wish windows wouldn't automatically corrupt my file system in 2 ways

2 Answers 2


Usually, if that Bad System Config thing pops up, it means that

  • the hive is corrupted, but this always gets spotted by the boot loader.
  • Your registry is shanked.

If you can't restart and use the good old "last known good configuration" selection, your only other options are reinstalling Windows. I've had the Bad_Sys_Config problem a couple of times, and each time I've ended up clean installing. That should be your last port of call should the reset windows option fails. I'll update this answer if I can think of anything else.

[EDIT] I thought of something else.

You said you have a Windows 7 computer? Create a windows 10 installation media on that, if you don't already have one, and you can choose to Repair windows or Reinstall. I'm sure that in the description of one (or both) of these actually has the old "Your files will be kept in a Windows.old folder" comment. This obviously is the best option for you if it has to go that far.

  • thanks... appears that they have removed last known good configuration on windows 10??
    – Blaine
    Apr 1, 2016 at 16:37
  • 1
    Oh, that's useful... Hold on, I'll update my answer... Apr 1, 2016 at 16:41
  • oh, thank you for the edit. Hopefully the windows.old folder still does what it needs to what with the file system being messed up
    – Blaine
    Apr 1, 2016 at 23:11
  • well, the option you are describing doesn't exactly exist. Closest thing would be the reset option. I tried what the top answer here reddit.com/r/Windows10/comments/3flfpf/… segjusted, and that stopped the bsod, but it just stays on the windows loading screen with no disk activity now :P. I'm getting to the point where i just have to reformat
    – Blaine
    Apr 2, 2016 at 6:52
  • hmm, tried a reset, the reset failed after wiping half the drive. gonna just reinsall windows now... Not sure how much of a pain that will be considering it's on a specific partition and i don't know the product key
    – Blaine
    Apr 2, 2016 at 7:28

If the "Last Known Good Configuration" boot option fails, you can always try restoring the SYSTEM and SOFTWARE hives from a backup that Windows makes (At least in some environments).

Step 1 - Boot into the Windows install disk or WinPE.
If using the install disk, follow the instructions here to open a command prompt.
Step 2 - Type the following commands to identify the volume letter of the OS volume.

Note: The disk number may be different. Replace it with the number of the drive that has the same capacity of the Windows drive.

sel disk 0
list vol

Navigate to "D:\Windows\system32\config" where 'D' is the drive letter where Windows is located.

Check to see if backups exist:

dir RegBack

If a SOFTWARE and SYSTEM file exist, continue to the next steps. Otherwise, you will have to reinstall Windows.

Make a backup of the current hives:


Copy the backups:


Reboot into Windows and try starting normally. If you manage to get into Windows, you may end up having to reactivate Windows (Especially in a KMS/Volume License environment where a computer must check in every X days to stay activated).

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