How to fix Error 1337 on Windows 11

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Troubleshooting Guide: Error 1337 – “The Security ID Structure Is Invalid”

Why This Error Happens

Error 1337 typically occurs when a Security Identifier (SID) associated with a user account, file, or registry object becomes corrupted, malformed, or references an entity that no longer exists in the Security Accounts Manager (SAM) database. This often happens after a botched user profile migration, a corrupted registry hive, or improper permissions being applied via tools like icacls or subinacl. It can also surface when third-party backup or permission-restoration software writes an incompatible SID format back into the Windows Access Control List (ACL).

Step-by-Step Resolution Guide

Step 1: Verify the Problematic SID via Command Line

  • Open Command Prompt as Administrator.
  • Run whoami /user to confirm your current account’s SID is valid and correctly formatted.
  • Run icacls "C:\Path\To\Affected\File_or_Folder" to inspect the ACL entries and look for broken or “Account Unknown” SID entries (they appear as long strings like S-1-5-21-... instead of a readable username).

Step 2: Reset Ownership and Permissions

  • Take ownership of the affected file/folder using: takeown /F "C:\Path\To\Affected\File" /R /D Y
  • Reset the ACL to remove the corrupted SID: icacls "C:\Path\To\Affected\File" /reset /T /C
  • Reapply correct permissions for your user account: icacls "C:\Path\To\Affected\File" /grant "%username%":F /T

Step 3: Check and Repair the SAM/Registry Hive

  • Open Registry Editor (regedit) and navigate to HKEY_LOCAL_MACHINE\SAM\SAM (requires taking ownership of this key first).
  • Run sfc /scannow in an elevated Command Prompt to repair corrupted system files that may store SID metadata.
  • Follow this with DISM /Online /Cleanup-Image /RestoreHealth to ensure the Windows image itself isn’t the source of corruption.

Step 4: Rebuild the User Profile (If Tied to a Specific Account)

  • Go to Settings > Accounts > Other Users and check if the affected profile shows as “Unknown Account” (a broken SID symptom).
  • If confirmed, back up user data from C:\Users\[ProfileName], then create a new local user profile via Settings > Accounts > Family & other users > Add account.
  • Migrate data manually to the new profile to avoid carrying over the corrupted SID reference.

Alternative or Verification Steps

  • Verify the fix: Re-run icacls "C:\Path\To\Affected\File" and confirm all entries now show readable usernames (e.g., DESKTOP-XXXX\User) instead of raw SID strings, and confirm the original operation (file access, permission change, etc.) completes without Error 1337.
  • Alternative fix: If the error persists on a domain-joined machine, run dsregcmd /status to check for a broken domain trust relationship, and consider rejoining the device to the domain/Azure AD to force regeneration of valid SIDs.