Repairing Windows installation that can't boot

Question

Background:

I have an Asus UX51VZ that will no longer boot into Windows. This was my dad's primary computer. I took it to a computer shop so they could fix the fans that came on at full speed all the time. I took out the two SSD harddrives beforehand to make sure they were safe. When I got the computer back, I put the drives back in, and everything worked fine for a day, then the fans started blowing hard again. I brought it back to the computer shop, but this time I left the drives in, thinking he might need them as he was going to try downgrading the BIOS. I didn't want to give him the password so he said he would use his own drive. Long story short he couldn't fix it, he refunded me, but it is now blue screening with my drives back in and will not boot.

Harddrive setup confusion:

This laptop supposedly comes with a RAID0 configuration for its 2 physical SSD drives (256GB each). There is a separate C: and a D: drive at ~237GB each. The BIOS SATA configuration is set to RAID. I can still see the folders in C: if I physically remove one drive and boot into recovery and command prompt. I can see the folders that were in D: if I enter into recovery with the other drive removed. Does this mean I'm not really in a RAID0 config? How am I able to enter recovery with either drive removed? Where is the recovery partition? What can I do to get more info on the proper hard drive setup?

Symptoms:

The laptop starts with ":( Your device ran into a problem and needs to restart." "Stop code: 0xC000021a."

Goal:

The data from both "C" and "D" has already been backed up. I am trying to recover the Windows installation 1) for fun to see if it's possible and 2) because I'd rather not reinstall all the programs that were installed.

Fixes I have tried:

It allows me to enter a recovery mode from where I tried:

1. Troubleshoot -> Startup Repair. Didn't work: "Startup Repair couldn't repair your PC." There is a log file at C:\windows\System32\Logfiles\Srt\SrtTrail.txt

2. Command prompt:

   • cd to c:\ and d:\ drives and all the folder and files seem to be there.

   • bootrec /fixMBR [worked]
     bootrec /fixBoot [access denied]
     bootrec /rebuildBCD [Total identfied Windows installations: 0]
     

     I then tried booting from a Windows 10 bootable USB drive I had laying around that had similar options:

     1. Reset this PC, keeping files. Fails at 1% and says nothing was changed.
     2. Command prompt:

     • bootrec /fixMBR [worked]
       bootrec /fixBoot [worked]
       bootrec /rebuildBCD [Total identfied Windows installations: 0]
       

     • diskpart
       list disk
       sel disk 0
       list volume
       sel volume 1 [100MB FAT32 partition]
       assign letter=b:
       exit
       cd /d b:\EFI\Microsoft\Boot\
       bootrec /fixboot
       ren BCD BCD.bak
       bcdboot c:\Windows /s b: /f ALL
       

       Did all this with the help of: https://www.bleepingcomputer.com/forums/t/620701/windows-10-wont-start-unable-to-repair-bcd-of-raid0/

     • chkdsk c: /r 
       

       This repaired some bad indexes but there were no bad sectors.

---

What else can I try?

Answer 1

This sounds like an UEFI/BIOS config problem. If you see all your files on both C: and D: then you must have been in RAID1, not RAID0. The BIOS/UEFI config should reflect this. I suspect the CMOS was reset at some point, and this setting reverted to setting the storage controller to a simple non-RAID configuration.

Answer 2

Please invest a little bit more into a better case description. There are thousands of laptops around and you can't expect others to know that the computer model you are mentionning is one.

Instead of throwing loads of recipes at your problem you have to proceed somewhat systematically.

• For some reason your fans always go full-speed. Typically this indicates a heat problem. Dust sometimes covers ventilation holes and restrict the necessary air flow.

• To exclude this possibility you have to open it and check for dust that either cover ventilation holes or covers cooler areas. Dust on a cooler works like an isolator and reduces thermal heat transfer.

• If you can exclude dust the next question is where the unwanted fan speed is coming from. If this is operating system related boot into a pendrive Linux and see if the fan behaviour changes.

• If that does not change anything, verify your bios settings and take a note of all of them - you might use a digital camera for that. You can try out a BIOS function labeled "reset to default settings". Does this change anything?

• Remove your laptop battery and let the laptop rest a night without the battery. On the next day start your machine and check if your BIOS settings have changed or if you got a message like "bad BIOS checksum". That would indicate that your typically replaceable mainboard battery is empty.

Next thing to do would be running a health check on your storage device using smartmontools or CrystalDiskInfo.

It is only after doing all this you should care about "operating system repair" at all. Data recovery is sometimes worth investing a lot of time. Trying to repair an installation is a waste of time, there is no guarantee of success and there are too many causes of error that one would not find.

Better invest the time into a fresh installation and create a full-system backup.

The installation of RAID0 on a laptop is foolish and suggests that there is some gamer using it trying to squeeze out another frame per second for his preferred game.

Read the comment from Joep van Steen. His word are always more polite then mine.

Answer 3

Your laptop is beyond the point where trying to repair the OS makes sense. Obtain a >=500GB external USB drive, boot up your live system, and backup your files off the borked laptop. When the hardware issues are resolved, install a fresh Windows 10: https://www.microsoft.com/software-download/windows10

There is a separate C: and a D: drive at ~237GB each, but those could just be partitions in the RAID0 setup, correct?

Correct, they could be, and they probably are. It's probably an awful hardware raid0 showing as a logical 500GB drive with 2 partitions at 237GB (your BIOS settings showing RAID0 indicate that it's a hardware RAID0)

Answer 4

RAID0

Striping

In RAID0 arrays data is striped. This means that data is split across the drives and reading/writing is a lot faster because all the drives are used in parallel.

Data

It also means that the data will be virtually useless and mostly unreadable if one or more drives are missing or the array config or controller stops working.

Bad news.

If you can read data and/or partition info from one or more single drives then your striped array is no more.

This means that it was either:

• Wiped at the repair shop, and any striped data was overwritten on one or more drive(s).

or

• Never really set up as RAID0. If any of your original data is still there, and readable, then this is most likely the case.

Recovery?

If it turns out your data is readable, then get an external USB hard-drive and a USB thumbdrive and follow along.

1. Power off your laptop.

2. Use a different computer to download and write a live version of a user-friendly Linux distro (for example Linux Mint) to the USB thumbdrive.

3. Safely remove the thumbrive when it has finished writing, and then plug it into your laptop.

4. Power the laptop on. Make sure you select the thumbdrive as you boot device before you continue.

5. Let it boot into the desktop environment, and then check if your internal drives can infact be recognized and mounted.

6. If your data is readable then plug in the external USB hard-drive. Mount (open) it, and copy all important data from your internal drives to the external one.

7. Make sure you use safe removal/safe eject or do a full proper shutdown before unplugging drives to avoid potential data loss.

Answer 5

SATA configuration in the BIOS where its set to RAID is not directly relevant to a supposed RAID configuration of your SSDs.

If you can see the data in C: which should have the Windows Folders and D: which may have additional files and folders that you may have created or added, then your SSDs may not have been setup in a RAID Configuration to begin with. Can you please confirm this?

You can have 1 drive with the SATA Configuration set to RAID. If what I think might be happening, it is entirely possible that your SATA configuration was always set to AHCI and not RAID which allowed one of your drives to boot into Windows. The RAID configuration may have come up after the BIOS was potentially downgraded.

RAID configuration of 2 drives can only be setup with RAID, if, and only if, there is a dedicated option/section in the BIOS which allows you to do so. If I had pictures of the various screens of the BIOS options and potentially how the system loads before the blue screen, I'll be able to advise you on what's happening.

Answer 6

I gotta say, since Windows Recovery was loaded, it'd seem like the OS is, at-least, partially exist. That indicates that the problem is not related to the RAID, and that it works. Otherwise, there wouldn't be any OS to boot from.

When your array will have a problem, you'll see a "no bootable devices" or "Waiting for PXE..." or something like that, depend on each computer and it's settings.

I can suggest 2 things:

• Can you get into safe mode? At the very least, to copy important files and then format the computer with new OS ( since that'd seem to be the problem ).
• Also, I saw someone who managed to boot from a similiar error code, by disabling "driver signature enforcement".

Source ( last messages in the thread ) : https://answers.microsoft.com/en-us/windows/forum/all/windows-10-bsod-error-0xc000021a/764d25ea-7122-46aa-8acf-9b8de31d6c92 )