Windows 10: C disk inaccessible, can't change to administrator

I mistakenly removed my computer permission to c drive. I am not able to change owner.I can't change to adminstrator using it and can't run command prompt as administrator.

:)

 

BSOD - Inaccessible Boot Device

The reset save files equivalent if successful should be the quickest method to get you backup and running.

The backup files then clean install is the best option as you fix many problems and start fresh.

The command prompt commands are all trial and error.

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INACCESSIBLE BOOT DEVICE after Win10 Update

1) Find a flash drive that you can format ( > or = 8 GB)
2) Create a bootable windows 10 iso:
Download Windows 10
4) Insert the flash drive into any USB port
5) Open the BIOS and temporarily change boot order so that you can boot using the flash drive.
6) When the iso loads choose language, time, currency, and keyboard, or click next
7) In the left lower corner click "repair your computer"
8) Click troubleshoot
9) Click command prompt
This should open: Administrator: X:\Windows\system32\cmd.exe > X:\Sources>

For all of the steps please use a camera or smart phone camera to take pictures and post images into the thread.

10) type: bcdedit | find "osdevice"
11) This may display osdevice partition=C:
12) type: diskpart
13) type: list disk
14) type: list volume
15) look under the column heading Fs for any volume that displayed RAW instead of NTFS
16) type: chkdsk /f /r G: (change G to the drive letter of the volume displaying RAW)
It may display "The first NTFS boot sector is unreadable or corrupt."
This may then convert the RAW volume to NTFS.
17) Type: exit
18) reboot to open the Windows advanced troubleshooting menu > command prompt > Administrator: X:\windows\system32\cmd.exe > X:\Sources>
19) type: bootrec /rebuildbcd
It may display:
Scanning all disks for Windows installations.
Please wait, since this may take a while...
Successfully scanned Windows installations.
Total identified Windows installations: 1
[1] D:\Windows
Add installation to boot list? Yes(Y)/No(N)/ALL(A):
20) Type: Y
The operation completed successfully.
X:\Windows>
21) Type: exit
22) reboot
See if the inaccessible boot device problem was fixed.

If the above did not fix the inaccessible boot device the next step is to remove the recent update:
23) Open command prompt > Administrator: X:\Windows\system32\cmd.exe > X:\Sources>
24) From the first command displaying the partition if the drive letter is different than C: please use the displayed drive letter for the next step
25) type: DISM /image:G:\ /cleanup-image /revertpendingactions (change G to the applicable drive letter)
26) This should remove the latest update and fix the inaccessible boot device.
27) If this does not fix the inaccessible boot device plan a registry repair.

Report into the thread your progress with images of the above steps.

 

C drive inaccessible

Hi Paritosh,

Thank you for giving us an opportunity to assist you with the query.

Apologize for the difficulties that you're experiencing in Windows 10.

Please be assured that we will do our best to help you.

• 
  Have you logged in as an administrator?
  
• 
  Have you made any changes to the computer prior to this issue?
  

An "Access Denied" error message can occur for one or more of the following reasons:

• The folder ownership has changed.
• You do not have the appropriate permissions.
• The file is encrypted.

Before we could reset the computer, let us try the following steps, and check if it helps.

Step 1: I suggest you to follow these steps to take the ownership of the drive.

• 
  Right click on Drive C and click
  Properties.
  
• 
  Switch to Security tab, click Edit and
  Add to add your user account, if it is not listed. Assign the
  full control permission for your own account and click OK.
  
• 
  Click Advanced, switch to Ownership tab and click
  Edit button.
  
• 
  Highlight your user account and click
  Apply, and then click OK.
  

Step 2: Let us try to disable to UAC settings and check.

• 
  Press Windows key + S and type
  User account control.
  
• 
  Select Change User Account Control Settings.
  
• 
  Move the slider to Never notify and click
  Ok.
  

Refer: "Access Denied" or other errors when you access or work with files and folders in Windows

https://support.microsoft.com/en-us/kb/2623670

(Applies to Windows 10 as well).

Hope it helps.

Let us know the status, we are glad to assist you further.