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FIX: Windows Defender Protection definition update failed
6 min. read
Updated onApril 3, 2024
updated onApril 3, 2024
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Windows Defenderis slowly but steadily getting a lot more trust from users. On the other hand, a lot of errors from the current and previousWindows 10major releases, are still an issue.
One common issue comes with a variation of the error codes and is accompanied by theProtection definition update failedmessage.
Today we’ll try to help you address this. In case you’re stuck with the error at hand, make sure to check the steps we provided below.
How do I fix the Protection definition update failed error?
1. Delete temporary files
The corruption within the system files, especially the ones concerning update distribution and storage is a rather common occurrence.
In this scenario, the previous iteration of theWindows Defendervirus definition might be corrupted. In order to address this, we recommend clearing all temporary files and restarting the update procedure.
Windows Defenderusually updates its definition automatically on a frequent basis and stores it in a dedicated folder. Deleting the content of the folder might help, as well.
After this, just restart your PC and make sure that it is connected to the internet.Windows Defendershould do the rest.
2. Restart the Windows Defender service
On the other hand, if the Defender itself shows signs of stalling or misbehaves in an unusual manner, there are additional steps to take.
Even thoughWindows Defenderis the built-in part of the Windows 10 shell, it can be disabled, and it also automatically turns off in presence of a third-party antivirus.
Now, even if you uninstalled the third-party antivirus prior to the occurrence of the update error, we encourage you to install one.
3. Install a third-party antivirus software
The worst thing that can happen to you while you’re using the Internet is being infected with malware or virus that will screw things over, steal your data, or cause other errors.
Therefore, you can’t rely solely on your Windows Defender to protect you, especially since the tool is ill-equipped to keep harmful software away.
Additionally, you’ll encounter errors such as theWindows Defender Protection definition update failedor theerror code 2145107924.
To avoid such things from occurring, you could install trustworthy third-party antivirus software that utilizes machine learning and other security methods to protect you.
For instance, ESET HOME Security Essential provides comprehensive protection for your PC against malware, cybercrime, snail-mail, and hackers.
To keep out threats, it makes use of the cloud’s power and many levels of detection. As a result, all possible attacks are blocked and you are shielded while you are working, social networking, playing online games, or exchanging data via removable storage.
If you have sensitive information and need to access potentially dangerous websites on a regular basis, you may require specialized software like ESET HOME Security Essential.
⇒Get ESET HOME Security Essential
4. Update Defender manually
Furthermore, updates aren’t Windows Update exclusives. Namely, you can download the recent definition for Windows 10 manually and install it just like any other program.
We all know how Windows Update for Windows 10 frequently causes issues of different kinds. That makes this nothing new.
5. Run the SFC scan
If the built-in, essential part of Windows 10 won’t work as intended, you can’t reinstall it. What you can do is run theSystem File Checkerand hope for the best.
This built-in system utility runs through the elevated Command Prompt. Its main purpose is to check for corruption within the system files. Once it gets what’s wrong, SFC will try to repair the affected files.
6. Reset your PC
Finally, if you’re still unable to resolve the issue at hand, we can go as far as recommending to reset your PC to factory settings.
It might seem discouraging at the first glimpse, but your files and apps won’t get affected whatsoever. In addition, the procedure is simple and quick – much better than the last resort.
This is, of course, a clean system reinstallation. After you reset your PC to factory values, theWindows Defenderupdate error should be gone.
That’s it. We hope at least one of the aforementioned solutions was helpful in addressing the Protection Definition update failed error in Windows 10.
We also recommend checking out thisarticle containing antivirus software with lifetime license. Take a look at the products and choose one that fits you best.
In case you’re aware of some alternatives or have a question regarding the ones we enlisted, make sure to tell us in the comments section below.
More about the topics:Microsoft Windows Defender
Aleksandar Ognjanovic
Aleksandar’s main passion is technology. With a solid writing background, he is determined to bring the bleeding edge to the common user. With a keen eye, he always spots the next big thing surrounding Microsoft and the Windows OS.
Focused on Windows errors and how to solve them, he also writes about the OS’s latest features as well as its interface.
In his free time, he likes to read, listen to music, and enjoy the nature. Hiking is one of his newly found passions.
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