Fix error 0x00000946 when loading user profile in Windows

When does this error actually happen?

You boot your Windows 10 or 11 machine, type your password, and instead of your desktop, you get a message box saying: "An error occurred while loading NERR_ProfileLoadErr the profile file" with the code 0X00000946. Sometimes it just says "The User Profile Service service failed the logon. User profile cannot be loaded."

This usually happens after a forced shutdown, a disk space outage, or a failed Windows update. I've seen it most often on Dell and HP business laptops after a Windows 10 22H2 update went sideways. You can still log in, but you get a temporary profile — your desktop is empty, your files are gone, and nothing works right.

What's actually broken?

The root cause is almost always a corrupted NTUSER.DAT file in your user profile folder (C:\Users\YourUsername). That file holds your registry settings for the user — things like desktop layout, Start menu preferences, and app settings. When Windows tries to load it and can't read it properly, it throws error 0x00000946. The file might be damaged from a bad write, or the permissions could be wrong.

I've also seen cases where the user profile registry key itself (under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList) gets a wrong SID path. But nine times out of ten, it's the NTUSER.DAT file that's the problem.

Fix 1: Repair the NTUSER.DAT file (the real fix)

This is the method that works best. You'll need to log in with a local admin account. If you only have one user account and it's broken, boot into Safe Mode with Networking — that'll give you the built-in Administrator account if you have it enabled, or you can use the sticky keys trick to get a command prompt. But let's assume you can log in with another admin account.

Log in with a different administrator account (or the built-in Administrator).
Open File Explorer and go to C:\Users. Find the folder with your broken username — it'll be the one without a padlock icon.
Right-click that folder and choose Properties.
Go to the Security tab, then click Advanced.
At the top, next to "Owner," click Change. Type Everyone and click Check Names (it'll underline it). Click OK.
Check the box that says Replace owner on subcontainers and objects. Click Apply. This takes a few seconds — don't interrupt it.
Now go back to the Security tab, click Edit, and add the group Everyone with Full control. Click Apply, then OK twice to close all dialogs.
Inside the broken user folder, look for a file called NTUSER.DAT. It might be hidden. At the top of File Explorer, click View and check Hidden items if you don't see it.
Right-click NTUSER.DAT and rename it to NTUSER.old. Yes, just .old — don't delete it yet in case you need it back.
Restart the computer. Log in with your regular account.

What you should see: Windows creates a fresh NTUSER.DAT from the default profile. Your desktop might look like a fresh install, but your files in Documents, Desktop, and Downloads should still be there under the old folder. If you don't see them, look in C:\Users\YourUsername\Desktop — they're likely there. You may need to copy them over if the profile structure is mixed up.

Expected outcome after step 9: After clicking Apply on the security settings, you should see a progress bar saying "Setting security information" or similar. When it's done, the folder icon might change to show a small padlock — that's normal. After renaming NTUSER.DAT, you won't see any error until you reboot.

Expected outcome after reboot: You get to your normal desktop with your old files (Documents, Pictures, etc.) still intact. Some app settings might be reset, but the core data is there.

Fix 2: Registry profile repair (when Fix 1 doesn't work)

If renaming NTUSER.DAT didn't fix the error, the profile registry key might point to the wrong path. Here's how to check:

Log in as an admin again.
Press Win + R, type regedit, and hit Enter.

Go to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

Look for a key that looks like S-1-5-21-... followed by a long string. You'll see a few of these — find the one that has a ProfileImagePath value that matches your broken username (e.g., C:\Users\YourUsername).
If there are two keys with the same SID but one ends in .bak, delete the non-.bak one, then remove the .bak extension from the second one. This tells Windows to use the backup profile.
If there's only one key, check that the ProfileImagePath is correct. If it's wrong, double-click it and type the correct path.
Close Regedit and restart.

Expected outcome: After deleting the corrupt key, the backup one takes over. When you log in, Windows should recognize the profile correctly.

Fix 3: System File Checker (if corruption spread)

Sometimes the corruption isn't just in the profile — it's in system files. Run this from an admin command prompt:

sfc /scannow

Let it finish. It'll take 10-20 minutes. If it finds corruption it can't fix, run:

DISM /Online /Cleanup-Image /RestoreHealth

Then run sfc /scannow again. Restart and try logging in.

Expected outcome: SFC will say "Windows Resource Protection found corrupt files and successfully repaired them" or "did not find any integrity violations." If it finds files it can't fix, DISM will pull clean files from Windows Update.

What to check if none of these work

If you're still getting error 0x00000946 after trying all three fixes, here's what I'd check next:

Disk errors: Run chkdsk C: /f from an admin command prompt. It'll schedule a scan on next boot. Reboot and let it run. Bad sectors on the drive can corrupt NTUSER.DAT repeatedly.
Antivirus interference: Temporarily disable your antivirus software (especially McAfee or Norton). I've seen them lock NTUSER.DAT during logon, causing this error. If disabling it fixes the issue, uninstall it and use Windows Defender instead.
Group Policy: If you're on a corporate machine, a group policy might be setting mandatory profiles or roaming profile paths that don't exist. Check with your IT department.
User profile disk quota: If the user's quota is exceeded, Windows might fail to write the profile. Check disk space on C: and expand it if needed.

Last resort: create a new local user account, copy your data over (Documents, Desktop, Downloads, AppData\Roaming for email signatures and browser bookmarks), and use that going forward. It's not elegant, but it works.