How to: Fix Windows Defender Protection Definition Update Failed

How to: Fix Windows Defender Protection Definition Update Failed

Here we can see, “How to: Fix Windows Defender Protection Definition Update Failed”

  • The Protection definition update failed error message appears when the OS is unable to update Windows Defender.
  • The Protection update failed Windows Defender error can be swiftly resolved by deleting temporary files on your computer.
  • Restart the Windows Defender service and upgrade the operating system to resolve any issues.
  • Installing third-party antivirus software for added security is also an option.

Users are slowly but surely gaining confidence in Windows Defender. On the other hand, many faults from earlier Windows 10 major releases continue to be a problem.

One prevalent issue is that the Protection definition update failed to notice, which is accompanied by various error codes.

We’ll attempt to assist you with this today. If you’re having trouble with the error, follow the steps we’ve provided below.

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What should I do if the Protection definition update fails?

1. Get rid of temporary files

  1. Type disk into the Windows Search bar to launch the Disk Cleanup tool.
  2. Click OK after selecting the System partition (C:).
  3. Select Cleanup system files from the drop-down menu.
  4. To entirely clear them, check the Temporary files box and click OK.
  5. Now, boot into Safe Mode and go to the following path, where you can erase the following folder’s contents:
    • C:\Windows\Software Distribution
  6. Check for changes in Defender’s behavior after restarting your computer.

The corruption of system files, particularly those related to updating delivery and storage, is typical.

The prior version of the Windows Defender virus definition could be corrupted in this case. We suggest deleting all temporary files and resuming the update process to resolve this.

Windows Defender’s definition is often updated on a regular basis and saved in a separate folder. Delete the folder’s contents if that doesn’t work.

Simply restart your computer and check that it is connected to the internet. Windows Defender should handle the rest.

2. Restart the Windows Defender service if it hasn’t already

  1. To open the Run command line, use Windows Key + R.
  2. Enter services.msc into the search box.
  3. Go to the individual Windows Defender services page.
  4. Right-click on it and select Properties from the drop-down menu for each service.
  5. Ensure that all of them are set to start automatically.

There are further actions to perform if the Defender itself exhibits evidence of stalling or misbehaving in an odd manner.

Even though Windows Defender is a built-in element of the Windows 10 shell, it may be stopped, and it also shuts off automatically when a third-party antivirus is installed.

Even if you uninstalled a third-party antivirus previous to the update problem, we recommend that you install one now.

3. Install antivirus software from a third-party provider

The worst thing that can happen to you while you’re online is to get infected with malware or a virus that will mess up your computer, steal your data, or create other problems.

As a result, you can’t rely on Windows Defender to keep you safe, especially since the utility isn’t designed to keep malicious software at bay.

Errors such as the Windows Defender Protection definition update failing or the error code 2145107924 are also common.

You could defend yourself by installing reputable third-party antivirus software that safeguards you using machine learning and other security measures.

For example, ESET Internet Security delivers comprehensive virus, cybercrime, snail-mail, and hacker protection for your PC.

It makes use of the cloud’s power and several levels of detection to keep threats at bay. As a result, while working, social networking, playing online games, or sending data via portable storage, all possible threats are prohibited, and you are protected.

You may need specialized software like ESET Internet Security if you have sensitive information and need to browse potentially risky websites frequently.

4. Keep Defender up to date. manually

  1. Search for Windows Update by pressing Windows Key + S.
  2. To check for updates, go to Windows Update and then to Check for Updates.
  3. Wait for Windows to check for and install any available updates.

Furthermore, updates are not limited to Windows Update. Specifically, you can manually download the most recent definition for Windows 10 and install it like any other software.

We’re all aware that Windows Update for Windows 10 frequently creates various problems. As a result, this isn’t something new.

5. Perform an SFC scan

  1. Type CMD into the Windows Search box, right-click the Command Prompt and execute it as an administrator.
  2. Type the following command in the command prompt: sfc /scannow
  3. Close the elevated command line and restart your computer after you’re finished.

You can’t restore the built-in, crucial portion of Windows 10 if it doesn’t perform as expected. You can only hope for the best if you run the System File Checker.

The elevated Command Prompt is used to access this built-in system utility. Its primary function is to look for corruption in system files. SFC will attempt to fix the impacted files once it has determined what is wrong.

6. Restart your computer

  1. To begin, make a backup of your data.
  2. To launch the Settings app, hit the Windows key + I after you’ve done that.
  3. Go to the Update & Security section of the menu.
  4. In the left pane, click Recovery.
  5. Under the Reset, this PC section, click the Get Started option.
  6. Click Next after selecting Keep your files.

Finally, if you’re still having trouble solving the problem, we recommend resetting your computer to factory settings.

It may appear disappointing at first, but your data and apps will not be harmed in any way. Furthermore, the operation is straightforward and quick – a vast improvement over the previous option.

Of course, this is a fresh system reinstall. The Windows Defender update problem should be gone after you restore your PC to factory settings.

That is all there is to it. We hope that at least one of the options mentioned above helped you with the Windows 10 Protection Definition update failed problem.


I hope you found this information helpful. Please fill out the form below if you have any questions or comments.

User Questions

1. Why isn’t Windows Defender up to date?

Sometimes the problem is only temporary, and all you have to do is restart your computer. Open the Windows Security programme. Select Virus and Threat Protection from the drop-down menu. Then click Check for Updates, and then Check for Updates again.

2. How can I make Windows Defender update automatically?

  1. By clicking the shield icon in the task bar or searching for Defender in the start menu, you can access the Windows Defender Security Center.
  2. Select the Virus & Threat Protection tile from the drop-down menu (or the shield icon on the left menu bar).
  3. Select Protection updates from the drop-down menu.
  4. To download new protection updates, click Check for updates (if there are any).

3. How can I repair Windows Defender antivirus’s security intelligence update?

Windows should be restarted. Go to Settings -> Update and Security -> Windows Update -> Check for Updates -> If you try again, the error message will be gone (for me).

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