What is NTUSER.DAT and How To Fix It?

Compatible with Windows 10, 8, 7, Vista and Windows XP

Overview of NTUSER.DAT


NTUSER.DAT is a type of DAT file associated with Microsoft Windows developed by Microsoft Corporation for the Windows Operating System. The latest known version of NTUSER.DAT is 6.3.9600.16384, which was produced for Windows 8.1. This DAT file carries a popularity rating of 5 stars and a security rating of "UNKNOWN".

Why Do I Have DAT Errors?

Quite simply, if Windows cannot properly load your NTUSER.DAT file, or your DAT file is infected with a virus or malware, you will encounter an error message. Please see "Causes of NTUSER.DAT Errors" below for more information.

When Do DAT Errors Occur?

DAT errors, such as those associated with NTUSER.DAT, most often occur during computer startup, program startup, or while trying to use a specific function in your program (eg. printing).

Common NTUSER.DAT Error Messages

The most common NTUSER.DAT errors that can appear on a Windows-based computer are:

  • "NTUSER.DAT error."
  • "NTUSER.DAT is missing."
  • "NTUSER.DAT not found."
  • "NTUSER.DAT failed to load."
  • "Failed to register NTUSER.DAT."
  • "Runtime Error: NTUSER.DAT."
  • "Error loading NTUSER.DAT."

These DAT error messages can appear during program installation, while a NTUSER.DAT-related software program (eg. Microsoft Windows) is running, during Windows startup or shutdown, or even during the installation of the Windows operating system. Keeping track of when and where your NTUSER.DAT error occurs is a critical piece of information in troubleshooting the problem.

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Causes of NTUSER.DAT Errors

NTUSER.DAT problems can be attributed to corrupt or missing files, invalid registry entries associated with NTUSER.DAT, or a virus / malware infection.

More specifically, these NTUSER.DAT errors can be caused by:

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How To Fix NTUSER.DAT Errors

Below is a list of troubleshooting steps to resolve your NTUSER.DAT problems. These troubleshooting steps get progressively more difficult and time consuming, so we strongly recommend attempting them in ascending order to avoid unnecessary time and effort.

Please Note: Click the [ Open ] image to expand the troubleshooting instructions for each step below. You can also click the [ Close ] image to hide the instructions as you proceed through each step.


Step 1: Repair Registry Entries Associated with Microsoft Windows

Sometimes NTUSER.DAT and other DAT system errors can be related to problems in the Windows registry. Several programs can share the same NTUSER.DAT file, but when these programs are uninstalled or changed, sometimes "orphaned" (invalid) DAT registry entries are left behind.

Basically, what this means is that while the actual file path may have changed, its incorrect former location is still recorded in the Windows registry. When Windows tries looking up these incorrect file references (file locations on your PC), NTUSER.DAT errors can occur. In addition, malware infection may have corrupted the registry entries associated with Microsoft Windows. Thus, these invalid DAT registry entries need to be repaired to fix the root of the problem.

Manually editing the Windows registry to remove invalid NTUSER.DAT keys is not recommended unless you are PC service professional. Incorrectly editing your registry can stop your PC from functioning and create irreversible damage to your operating system. In fact, one misplaced comma can prevent your PC from booting entirely!

Because of this risk, we highly recommend using a trusted registry cleaner such as (Developed by Microsoft Gold Certified Partner) to scan and repair any NTUSER.DAT-related registry problems. Using a automates the process of finding invalid registry entries, missing file references (like the one causing your NTUSER.DAT error), and broken links within the registry. A backup is automatically created before each scan, with the ability to undo any changes in a single click, protecting you against the possibility of PC damage. The best part is that can also dramatically improve system speed and performance.

Caution: Unless you an advanced PC user, we DO NOT recommend editing the Windows registry manually. Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows. We do not guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

To manually repair your Windows registry, first you need to create a backup by exporting a portion of the registry related to NTUSER.DAT (eg. Microsoft Windows):

  1. Click the Start button.
  2. Type "command" in the search box... DO NOT hit ENTER yet!
  3. While holding CTRL-Shift on your keyboard, hit ENTER.
  4. You will be prompted with a permission dialog box.
  5. Click Yes.
  6. A black box will open with a blinking cursor.
  7. Type "regedit" and hit ENTER.
  8. In the Registry Editor, select the NTUSER.DAT-related key (eg. Microsoft Windows) you want to back up.
  9. From the File menu, choose Export.
  10. In the Save In list, select the folder where you want to save the Microsoft Windows backup key.
  11. In the File Name box, type a name for your backup file, such as "Microsoft Windows Backup".
  12. In the Export Range box, be sure that "Selected branch" is selected.
  13. Click Save.
  14. The file is then saved with a .reg file extension.
  15. You now have a backup of your NTUSER.DAT-related registry entry.

The next steps in manually editing your registry will not be discussed in this article due to the high risk of damaging your system. If you would like to learn more about manual registry editing, please see the links below.

We do not claim any responsibility for the results of the actions taken from the content linked below - complete these tasks at your own risk.

Windows XP

Windows 7

Windows Vista
http://support.microsoft.com/kb/2688326 - LetMeFixItMyselfAlways


Step 2: Conduct a Full Malware Scan of Your PC

There is a chance that your NTUSER.DAT error could be related to a malware infection on your PC. These malicious intruders can damage, corrupt, or even delete DAT-related files. Furthermore, there's a possibility that the NTUSER.DAT error you are experiencing is related to a component of the malicious program itself.

Tip: If you do not already have a malware protection program installed, we highly recommend using Emsisoft Anti-Malware (). They offer a malware removal guarantee that is not offered by other security software.


Step 3: Clean Out Your System Junk (Temporary Files and Folders) With Disk Cleanup (cleanmgr)

Over time, your computer accumulates junk files from normal web surfing and computer use. If this junk isn't occasionally cleaned out, it can cause Microsoft Windows to respond slowly or provides an NTUSER.DAT error, possibly due to file conflicts or an overloaded hard drive. Cleaning up these temporary files with Disk Cleanup might not only solve your NTUSER.DAT error, but can also dramatically speed up the performance of your PC.

Tip: Although Disk Cleanup is a wonderful built-in tool, it will not completely clean up all of the temporary files on your computer. Other programs that you frequently use such Microsoft Office, Firefox, Chrome, Live Messenger, and hundreds of other programs are not cleaned up with Disk Cleanup (including some Microsoft Corporation programs).

Because of the shortcomings of the Windows Disk Cleanup (cleanmgr) tool, we highly recommend using a specialized hard drive cleanup / privacy protection software such as (Developed by Microsoft Gold Partner) to clean up your entire computer. Running once per day (using automatic scanning) will ensure that your computer is always clean, running fast, and free of NTUSER.DAT errors related to temporary files.

How to run Disk Cleanup (cleanmgr) (Windows XP, Vista, 7, 8, and 10):

  1. Click the Start button.
  2. Type "command" in the search box... DO NOT hit ENTER yet!
  3. While holding CTRL-Shift on your keyboard, hit ENTER.
  4. You will be prompted with a permission dialog box.
  5. Click Yes.
  6. A black box will open with a blinking cursor.
  7. Type "cleanmgr" and hit ENTER.
  8. Disk Cleanup will begin calculating how much occupied disk space you can reclaim.
  9. The Disk Cleanup dialog box will appear with series of checkboxes you can select. In most cases, the "Temporary Files" category will occupy the most disk space.
  10. Check the boxes of the categories you want to clean and click OK.


Step 4: Update Your PC Device Drivers

NTUSER.DAT errors can be related to corrupt or outdated device drivers. Drivers can work one day, and suddenly stop working the next day, for a variety of reasons. The good news is that you can often update the device driver to fix the DAT problem.

Finding the exact driver for your NTUSER.DAT-related hardware device can be extremely difficult, even directly on the Microsoft Corporation or related manufacturer's website. Even if you are experienced at finding, downloading, and manually updating drivers, the process can still be very time consuming and extremely irritating. Installing the wrong driver, or simply an incompatible version of the right driver, can make your problems even worse.

Because of the time and complexity involved in updating drivers, we highly recommend using a driver update tool such as DriverDoc (Developed by Microsoft Gold Partner) to automate the process.

DriverDoc updates all of your PC device drivers, not just those associated with your DAT error. DriverDoc's proprietary One-Click Update™ technology not only ensures that you have correct driver versions for your hardware, but it also creates a backup of your current drivers before making any changes. Maintaining a driver backup provides you with the security of knowing that you can rollback any driver to a previous version if necessary. With updated device drivers, you can finally unlock new hardware features and improve the speed and performance of your PC.

Please Note: Your NTUSER.DAT may not be related to hardware driver problems, but it's always a good idea to ensure all of your PC device drivers are up-to-date to maximize PC performance.


Step 5: Utilize Windows System Restore to "Undo" Recent System Changes

Windows System Restore allows you to "go back in time" with your PC to help fix your NTUSER.DAT problems. System Restore can return your PC's system files and programs back to a time when everything was working fine. This can potentially help you avoid hours of troubleshooting headaches associated with DAT errors.

Please Note: Using System Restore will not affect your documents, pictures, or other data.

To use System Restore (Windows XP, Vista, 7, 8, and 10):

  1. Click the Start button.
  2. In the search box, type "System Restore" and hit ENTER.
  3. In the results, click System Restore.
  4. Enter any administrator passwords (if prompted).
  5. Follow the steps in the Wizard to choose a restore point.
  6. Restore your computer.


Step 6: Uninstall and Reinstall the Microsoft Windows Program Associated with NTUSER.DAT

If your NTUSER.DAT error is related to a specific program, reinstalling Microsoft Windows-related software could be the answer.

Instructions for Windows 7 and Windows Vista:

  1. Open Programs and Features by clicking the Start button.
  2. Click Control Panel on the right side menu.
  3. Click Programs.
  4. Click Programs and Features.
  5. Locate NTUSER.DAT-associated program (eg. Microsoft Windows) under the Name column.
  6. Click on the Microsoft Windows-associated entry.
  7. Click the Uninstall button on the top menu ribbon.
  8. Follow the on-screen directions to complete the uninstallation of your NTUSER.DAT-associated program.

Instructions for Windows XP:

  1. Open Programs and Features by clicking the Start button.
  2. Click Control Panel.
  3. Click Add or Remove Programs.
  4. Locate NTUSER.DAT-associated program (eg. Microsoft Windows) under the list of Currently Installed Programs.
  5. Click on the Microsoft Windows-associated entry.
  6. Click the Remove button on the right side.
  7. Follow the on-screen directions to complete the uninstallation of your NTUSER.DAT-associated program.

Instructions for Windows 8:

  1. Hover the cursor in the bottom left of the screen to produce the Start Menu image.
  2. Right-Click to bring up the Start Context Menu.
  3. Click Programs and Features.
  4. Locate NTUSER.DAT-associated program (eg. Microsoft Windows) under the Name column.
  5. Click on the Microsoft Windows-associated entry.
  6. Click the Uninstall/Change on the top menu ribbon.
  7. Follow the on-screen directions to complete the uninstallation of your NTUSER.DAT-associated program.

After you have successfully uninstalled your NTUSER.DAT-associated program (eg. Microsoft Windows), reinstall the program according to the Microsoft Corporation instructions.

Tip: If you are positive that your DAT error is related to a specific Microsoft Corporation program, uninstalling and reinstalling your NTUSER.DAT-related program will likely be the solution to your problem.


Step 7: Run Windows System File Checker ("sfc /scannow")

System File Checker is a handy tool included with Windows that allows you scan for and restore corruptions in Windows system files (including those related to NTUSER.DAT). If System File Checker finds a problem with your DAT or other critical system file, it will attempt to replace the problematic files automatically.

To run System File Checker (Windows XP, Vista, 7, 8, and 10):

  1. Click the Start button.
  2. Type "command" in the search box... DO NOT hit ENTER yet!
  3. While holding CTRL-Shift on your keyboard, hit ENTER.
  4. You will be prompted with a permission dialog box.
  5. Click Yes.
  6. A black box will open with a blinking cursor.
  7. Type "sfc /scannow" and hit ENTER.
  8. System File Checker will begin scanning for NTUSER.DAT and other system file problems (be patient - the system scan may take a while).
  9. Follow the on-screen commands.


Step 8: Install All Available Windows Updates

Microsoft is constantly updating and improving Windows system files that could be associated with NTUSER.DAT. Sometimes resolving your DAT problems may be as simple as updating Windows with the latest Service Pack or other patch that Microsoft releases on an ongoing basis.

To check for Windows Updates (Windows XP, Vista, 7, 8, and 10):

  1. Click the Start button.
  2. Type "update" into the search box and hit ENTER.
  3. The Windows Update dialog box will appear.
  4. If updates are available, click the Install Updates button.


Step 9: Perform a Clean Installation of Windows

Caution: We must emphasize that reinstalling Windows will be a very time-consuming and advanced task to resolve NTUSER.DAT problems. To avoid data loss, you must be sure that you have backed-up all of your important documents, pictures, software installers, and other personal data before beginning the process. If you are not currently backing up your data, you need to do so immediately () to protect yourself from permanent data loss.

This step is your final option in trying to resolve your NTUSER.DAT issue. Reinstalling Windows will erase everything from your hard drive, allowing you to start again with a fresh system. Furthermore, a clean install of Windows will also quickly clean out any and all "junk" that has accumulated over the normal usage of your computer.

Please Note: If NTUSER.DAT errors still persist after a clean install of Windows, your DAT problem MUST be hardware related. If that is the case, then it is likely you will need to replace the associated hardware causing the NTUSER.DAT error.

Recommendation: .
Filename: NTUSER.DAT Latest Known Version: 6.3.9600.16384
Developer: Microsoft Corporation File Size (Bytes): 262144
Software: Microsoft Windows Operating System: Windows 8.1
MD5: 92f767470b538072038bfac205792493
SHA1: 20011d8b054ae838fd88e5d1f1ad8cddc0cff5ac
SHA256: 83e31c790442d5b796a90a17fd15877dd53c2ecbff4ef7dad95c46d462a99b1d

Operating System Information

NTUSER.DAT error messages can occur in any of the following Microsoft Windows operating systems:

Are You Still Experiencing NTUSER.DAT Issues?

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Jay Geater

About The Author: is the President and CEO of talonlibre Corporation, a global software company focused on providing innovative utility software. He is a lifelong computer geek and loves everything related to computers, software, and new technology.

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