FIX: An unexpected problem occurred in Windows Defender

Madalina Dinita
by Madalina Dinita
Madalina has been a Windows fan ever since she got her hands on her first Windows XP computer. She is interested in all things technology, especially emerging technologies -- AI and DNA computing in... Read more
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  • Windows Defender is the first line of defense against viruses and malware. What can you do if you get the Windows Defender unexpected error?
  • Switching to stronger antivirus software that is known for being error-free is a quick way to deal with the problem.
  • One other method to solve the issue is removing leftover files with specialized uninstaller and removal software.
  • Performing a clean boot and a System File Check scan are also some good solutions.
How to fix Windows Defender an unexpected problem occurred error
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More and more Windows Defender users are reporting they can’t turn on Microsoft’s built-in antivirus program due to various errors.

Some of them can’t install the latest updates, while others can’t get the software to perform a quick scan. Overall, this will leave PCs open to malware and other harmful software.

Today, we’re adding a new issue to the list, as many users have reported they can’t turn on the real-time protection feature in Windows Defender due to An unexpected problem occurred error.

There is no particular error code for this error, only a pop-up window asking users to install the latest updates.

Windows Defender offers solid protection, but many users reported An unexpected problem occurred while trying to start the tool.

There are other issues that can affect Windows Defender and these are some of the most common ones:

  • Windows Defender unexpected error sorry we ran into a problem – Sometimes you might get this error message while trying to start Windows Defender. If this happens, be sure to remove all files associated with your antivirus and check if that solves the problem.
  • Windows Defender security center not working – If you encounter this issue, the problem might be your services, so be sure to reset them and check if that helps.
  • Windows Defender unexpected error please try again – This is another common problem that can occur in Windows 10. If you encounter this problem, be sure to update Windows 10 and check if that solves the issue.
  • Windows Defender keeps stopping – Many users reported that Windows Defender keeps stopping on their PC. If you encounter this problem, be sure to check your registry.

For the time being, Microsoft’s Support engineers haven’t replied to this thread, and we couldn’t find a specific solution for this error either.

Fortunately, there are some general workarounds available to fix common Windows Defender issues, and we suggest you try them out. Maybe one of the workarounds listed below can solve this issue.

Quick Tip:

Windows Defender is not the best security tool out there. There are many safer bets for you, that include lots of other features and extra layers of protection.

We suggest switching to a specialized antivirus software. You should look for one that uses advanced AI and machine learning to detect even the newest threats out there.

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How can I fix An unexpected problem occurred error?

1. Use antivirus specific removal tools

Completely uninstall your old antivirus programs using this antivirus removal tool.  Download and run the tool available for the antivirus you used before installing Windows Defender.

Then restart your computer and Windows Defender should be able to install the latest updates. In addition to antivirus removal tools, you can also use uninstaller applications for this job.

If you’re not familiar, uninstaller apps are specially designed to uninstall any program and remove all its files and registry entries from your PC.

By using this tool, you’ll completely remove any application from your PC along with any leftover files. As a result, you will prevent any remnant files from interfering with Windows Defender.

The best part is that there is a generous 60-day money-back guarantee feature included, so you will have plenty of time to convince yourself of its usefulness absolutely risk-free.

There is even a lightweight, portable version that does not require any downloading, and you can simply store it on a USB flash drive and use it directly from there on any PC.

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2. Clean boot your computer

  1. Press Windows Key + R and enter msconfig. Now press Enter or click OK.
    Windows Defender unexpected error sorry we ran into a problem
  2. System Configuration window will now appear. Go to the Services tab and check Hide all Microsoft services. Now click Disable all button.
    Windows Defender unexpected error sorry we ran into a problem
  3. Now go to the Startup tab and click Open Task Manager.
    Windows Defender security center not working
  4. Once the Task Manager opens, you’ll see a list of startup applications. Right-click the first entry on the list and choose Disable from the menu. Repeat this step for all startup applications on the list.
    Windows Defender unexpected error please try again
  5. After you disable all startup applications, close Task Manager, and go back to System Configuration window. Click Apply and OK and restart your PC.
    Windows Defender keeps stopping

Third-party applications can sometimes interfere with Windows Defender and cause an unexpected error sorry we ran into a problem Windows Defendererror message to appear.

This can be caused by third-party startup applications, and in order to fix this issue, you need to perform a Clean boot. This is rather simple and you can do it by following these steps.

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Once your PC restarts, check if the problem still persists. If not, it means that one of the disabled apps or services was causing it.

If you want to find out which app is the problem, disable apps and services one by one or in groups, save changes, and restart your PC.

Keep in mind that you’ll have to repeat this several times. Once you find the problematic application, you can disable it or remove it from the device.

3. Check your system files

  1. Press Windows Key + X to open the Win + X menu and choose Command Prompt (Admin) or PowerShell (Admin) from the menu.
    Windows Defender unexpected error sorry we ran into a problem
  2. Type the following command and hit Enter: sfc /scannow
    Windows Defender keeps stopping

The System File Checker tool repairs corruption in system files.

Use this tool to verify whether Windows Defender is corrupted or not, which could explain why you receive the Windows security unexpected error error message.

If the SFC scan doesn’t solve the problem, or if you can’t run an SFC scan at all, you might be able to fix the issue by using DISM scan instead. To do that, just do the following:

  1. Start Command Prompt as administrator.
  2. When Command Prompt starts, enter the following command and press Enter: DISM /Online /Cleanup-Image /RestoreHealth
  3. DISM scan will now start. Keep in mind that the DISM scan can take up to 30 minutes, so don’t interrupt it.
    Windows Defender security center not working
  4. Once the DISM scan is finished, check if the problem still persists.

If the issue is still present, or if you couldn’t run an SFC scan before, be sure to repeat the SFC scan once again and check if that fixes the problem.

4. Restart the Security Center Service

  1. Press Windows key + R, then launch Run.
  2. Type services.msc and hit Enter.
    Windows Defender security center not working
  3. In Services, search for Security Center.
  4. Right-click on Security Center and click on Restart.
    Windows Defender unexpected error please try again

According to users, sometimes certain services can cause An unexpected problem occurred error to appear.

However, this is just a temporary problem and you can fix it simply by resetting the problematic service. To do that, you just need to follow the aforementioned steps.

In addition to the Security Center service, some users are also recommending resetting Windows Defender Service, so be sure to do that as well.

After resetting the required services, check if the problem still persists.

5. Make sure that your Windows is up to date

  1. Press Windows Key + I to open the Settings app.
  2. Now go to the Update & Security section.
  3. Click Check for updates button in the right pane.

Windows will now check for available updates and download them in the background. Once the updates are downloaded, they will be installed automatically as soon as you restart your PC.

Keeping your PC up to date is important, and if you’re having problems with Windows Defender, be sure to update Windows and check if that solves the issue.

Windows Defender is a core component of Windows 10, and if you’re getting An unexpected problem occurred error message, you might be able to fix the problem simply by updating your Windows.

By default, Windows 10 will automatically install the missing updates, but sometimes you might miss an update due to certain bugs. However, you can always check for updates manually.

6. Make changes to your registry

  1. Press Windows Key + R and enter regedit. Now press Enter or click OK.
    Windows Defender unexpected error please try again
  2. When Registry Editor opens, in the left pane navigate to the following path: HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindows Defender
  3. In the right pane, double-click DisableAntiSpyware DWORD.
  4. If this value isn’t available, you’ll need to create it by right-clicking the empty space and choosing New > DWORD (32-bit) Value.
    Windows Defender keeps stopping
  5. Set the Value data to 0 and click on OK to save changes.
    Windows Defender unexpected error sorry we ran into a problem

According to users, if Windows Defender is giving you An unexpected problem occurred error, you might be able to fix it simply by changing your registry.

After doing that, the problem with Windows Defender should be resolved and you should be able to use it without any problems.

An unexpected problem occurred error can prevent you from running Windows Defender, but as you can see, this issue can be easily resolved.

If you’re looking to change your defense system, take a closer look at this useful list of the best antivirus software with lifetime licenses and choose the one that you like.

Not being able to use Windows Defender can be a security risk, but we hope that you managed to solve this problem using one of our solutions.

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