Windows defender or security essentials error 0x80073b01 specifies that there is an interference between Windows Defender and another security program present on the computer.

Here at Bobcares, we have seen several such Windows-related errors as part of our Server Management Services for web hosts and online service providers.

Today we’ll take a look at the causes for this error and see the fix.

What causes Windows defender or security essentials error 0x80073b01 to occur

The error 0x80073b01 specifies that there is an interference between Windows Defender and another security program present on the computer. Or there are corrupted system files that prevent it from working properly.

Also, you may come across this error message while trying to turn on Windows Defender.

This error message appears along with a few other symptoms such as not being able to find Windows Defender in the Control Panel, and not being able to start it up.

For instance, the error appears as below.

How we resolve the ‘Windows defender or security essentials error 0x80073b01’

Now let’s take a look at how our Support Engineers resolve this error for our customers.

Solution 1: Uninstall any third-party security software

The first thing that we try is to uninstall any third-party security software. It is well known that third-party software such as Norton or McAfee interferes come with the built-in security features of Windows. So it is highly likely that this might be the problem. Here are the steps that we follow to disable it.

1. First, we press the Windows key on the keyboard and type in Change or remove a program.
2. Next, from the list of software currently installed, we find third-party security software.
3. Then we click on it, and press Uninstall near the top of the window. We follow the instructions until the software is removed.
4. After that, we check the website of the manufacturer of the antivirus software. Also, we look for a removal tool. This always helps because oftentimes, when we uninstall the software, it leaves behind files and registry entries that might still mess things up.
5. Finally, we restart the device. Windows Defender now works just fine.

Solution 2: Use the Registry Editor

The Registry Editor is a powerful tool that is often used to fix issues. The thing is that we must be aware of which keys to edit, as messing up the wrong key can be fatal for the computer. Here are the instructions that we follow.

1. First, we press the Windows and R keys simultaneously. Then appears a window where we type in Regedit and press enter to open the Registry Editor.

2. After that, we use the left side navigation pane to go to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\ImageFileExecutionOptions\

and delete msseces.exe entry. Next, we go to:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\DisallowRun

and again, we delete the msseces.exe entry.

3. Finally, we restart the computer, and then we run Windows Defender without any issues.

Solution 3: Run the System File Checker tool

The System File Checker tool is very useful in scanning, finding, and repairing corrupt system files. If the main cause of the Windows Defender problem is a corrupt system file, this method will fix it.

1. First, we press the Windows key and type in Right-click the result and choose Run as administrator.
2. Then we type in the following command, and press Enter to execute it:

sfc /scannow

3. Once the command is 100% complete, the problem should be fixed.

Solution 4: Check for updates

Another cause for the problem is not having all the latest updates installed. Here are the steps to update.

1. First, we press the Windows key and type in Windows Update, then we open the result.
2. Next, we click Check for updates and see if there are any updates available. If there are, we proceed with installing them. Finally, we reboot when they are done.

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Conclusion

In short, this error specifies that there is an interference between Windows Defender and another security program present on the computer. Today, we saw the solution provided by our Support Engineers.