Microsoft Windows Error Code 0xC0000073: How to Fix It

Medium 1-2 hours Medium Severity Verified June 2026
Error Code
0xC0000073
Brand
Microsoft Windows
Product Type
operating_system
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours
Error code 0xC0000073 (STATUS_NONE_MAPPED) indicates Windows cannot map a security identifier (SID) to a name. This often occurs due to corrupted user profiles or permissions issues, preventing you from logging in or accessing certain files.
Ad

Tools You'll Need

How to Fix Error Code 0xC0000073

  1. Boot into Safe Mode

  2. Back Up Your Data

    Do not skip this step, as profile corruption can lead to data loss.
  3. Run System File Checker

  4. Check Disk for Errors

    Chkdsk may take a long time; do not interrupt it.
  5. Restore User Profile

    Be careful when copying files; do not copy the entire profile folder as it may bring back the corruption.
  6. Repair Registry (Advanced)

    Editing the registry is risky; back it up first.
  7. Perform System Restore

    System Restore may remove recently installed programs, but your personal files should remain.
  8. Reset or Reinstall Windows

    Back up all data before resetting or reinstalling.
Ad

When to Call a Professional

If you cannot boot into Safe Mode or your data is critical, seek professional data recovery services. A technician can repair the profile or recover files without risking further damage.

Frequently Asked Questions

What causes error 0xC0000073 in Windows?
This error usually stems from a corrupted user profile, damaged system files, or permission issues where Windows cannot map a security identifier (SID) to a name. It may appear after a failed update, disk errors, or software conflicts.
Can I fix error 0xC0000073 without losing data?
Yes, in most cases you can fix it without data loss by booting into Safe Mode and backing up your data first, then running system repairs or restoring a backup of the user profile.
Is error 0xC0000073 the same as the Blue Screen of Death?
No, this error typically appears as a dialog box during login or when accessing files, not a full blue screen crash. However, it can prevent you from logging in normally.
How do I create a new user profile to fix this error?
Boot into Safe Mode, go to Settings > Accounts > Family & other users, and add a new user. Log out and log in as the new user. Then copy your data from the old profile folder (C:\Users\OldUsername) to the new one.
What if none of the steps work?
If all DIY steps fail, consider using System Restore, Reset this PC, or a clean reinstall of Windows. For data recovery, consult a professional. If the hard drive is failing, replace it and restore from backup.