D Drive Denied Access. Changed permissions and cancelled half way.

Recover ownership of D:\ from an elevated Command Prompt, establish valid permissions at the drive root, and then reset child items so they inherit those permissions.

Repair the interrupted permission change

These commands change security information, not file contents. However, resetting inheritance removes custom per-folder permissions, so do not use this procedure if D: contains another Windows installation or folders that intentionally require different access rules.

1. Sign in to an administrator account.
2. Open Start, type Command Prompt, right-click it, and select Run as administrator.
3. Take ownership of the drive for the built-in Administrators group:

takeown /f D:\ /a /r /d Y

/a assigns ownership to Administrators, while /r processes files and subfolders recursively. The operation can take considerable time; allow it to finish rather than cancelling it again. Some protected-folder warnings can occur. ^1^

4. Establish permissions at the root of D::

icacls D:\ /inheritance:e
icacls D:\ /grant:r "*S-1-5-32-544:(OI)(CI)F"
icacls D:\ /grant:r "*S-1-5-18:(OI)(CI)F"

These entries give Administrators and SYSTEM full control and make the permissions inheritable by files (OI) and folders (CI). Microsoft documents these inheritance flags and the /grant:r behavior. ^2^

5. Grant access to the standard account. Replace COMPUTER\UserName with that account’s actual name:

icacls D:\ /grant:r "COMPUTER\UserName:(OI)(CI)F"

To find the exact account name, sign in to that account and run whoami, or check Settings → Accounts → Your info.

6. Reset the permissions below the drive root so all existing children inherit the repaired root permissions:

icacls D:\* /reset /t /c

/t processes subfolders, /c continues past individual errors, and /reset replaces child ACLs with inherited defaults. ^2^

7. Restart Windows, sign in to the standard account, and open D:. File Explorer should again show the capacity bar and allow access.

This ownership-first, permissions-second sequence also matches the accepted recovery procedure for a drive reporting “Unable to display current owner” and refusing recursive access. ^3^

Important notes

• Seeing NTFS instead of the storage-size bar does not mean the volume was converted or erased; NTFS is the file system. Explorer may be unable to read enough volume information while access to the drive root is denied.
• Do not grant Everyone full control.
• Do not alter System Volume Information separately. It is normally protected, and isolated access-denied messages for that folder do not mean the repair failed.
• If takeown or icacls reports widespread I/O errors—not merely access errors—stop modifying permissions and check the drive’s health or recover the data to another disk.
• If only particular files remain inaccessible after the repair and their Attributes include E, they may use Encrypting File System (EFS). Such files must be decrypted by the account that encrypted them or by its recovery agent; ordinary permission changes cannot decrypt them. ^4^

References

1. takeown
2. icacls
3. How to fix permissions - Microsoft Q&A
4. Access is denied error message appears when permissions are correct