Windows Defender error code 0x800705b4 generally appears when Windows Defender refuses to open. If any user doesn’t use any third-party antivirus software, then this error can threaten the system. 

If you have any third-party installed antivirus software, then you have to disable the software. Basically, Windows users can notice error code 0x800705b4 when starting the Windows Defender. So you need to fix the error with utmost sincerity.

Easy Fixes to Eradicate Windows Defender Error Code 0x800705b4

We have investigated and found numerous fixes to get rid of the error. These fixes will help your system to bring back Windows Defender to its working state. We have a small recommendation for you. You can create a restore point on your system before applying fixes. This will restore your system to a preferable point of time if anything goes wrong. 

Fix 1: Deactivate Third-party Antivirus

Deactivate Third-party Antivirus

If you have any third-party installed antivirus on your system, then you should first disable the antivirus. Follow the steps below to disable third-party antivirus.

  1. Right-click on the desktop icon of the third-party antivirus software.
  2. Choose the Disable option from the drop-down menu.
  3. Next, you have to select the time span for which you want to disable the antivirus. You can choose a short time like 15 or 30 minutes. 

Once you have done the step, try opening the Windows Defender tool. Check if you can notice Windows Defender error code 0x800705b4 anymore.

Fix 2: Activate Windows Firewall

Activate Windows Firewall

You may opt for this fix if the first fix fails to perform. Make sure that Windows Firewall is active or not on your Windows system. Check the following process out to eradicate the error.

  1. Launch Control Panel by pressing Win+I keys, simultaneously.
  2. Choose the System and Security option. Then opt for the Windows Firewall option.
  3. Click on the ‘Turn Windows Firewall on or off’ option from the left pane of the window.
  4. Choose ‘Turn on Windows Firewall and restart your PC’ option. 

Wait until the system restarts and try launching Windows Defender. Proceed to the next fixes if you still notice the same error.

Fix 3: Launch the Windows Defender Services

Launch the Windows Defender Services

If the first two fixes went in vain, then you can opt for this fix. You need no additional tools to apply this fix. You need the Run dialog box to operate this fix.

  1. Press and hold Win+R from keyboard to launch Run dialog box. 
  2. Fill it with ‘services.msc’ and tap on OK. this will show all the services on your system.
  3. You have to locate the following services: 
  1. Windows Defender Antivirus Network Inspection Service
  2. Windows Defender Antivirus Service
  3. Windows Defender Security Center Service
  4. You have to double-click on each service. Check if the startup type of each service is set as automatic. You have to click on the Start option if the services are not active. 
  5. Click on OK and Apply to save the changes you made.

Next, you can reboot your system. Then, launch Windows Defender to check if the error code persists still now.

Fix 4: Fix the Registry

Fix the Registry

You might have to look into the Registry Editor if you are still dealing with the error. Just follow these simple instructions below to fix any mishap with the registries.

  1. Launch Run dialog box using the same procedure depicted above. Type ‘regedit’ and click on Ok. This will open the Registry Editor. 
  2. You have to navigate the following path: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender.
  3. Check if you have clicked on Windows Defender from the left pane of the window. 
  4. Double-click on the ‘DisableAntiSpyware’ option. Click on OK to disable.

Now, again try to launch Windows Defender and check if the Windows Defender error code 0x800705b4 has resolved.  

Fix 5: Run SFC and DISM Scan 

Run SFC and DISM Scan 

You can notice an error code 0x800705b4 when starting Windows Defender if the corresponding files are corrupt. You have to simply run an SFC scan first. If it doesn’t work, then you may opt for a DISM scan too. Let’s check out the process.

  1. Press Win+X keys from the keyboard at the same time. Choose Command Prompt(Admin) option from the context menu. This fix won’t work without administrator privilege. So make sure that you opt for the Admin in the braces.
  2. You have to provide the following command and hit Enter: “sfc/scannow”.
  3. Wait until the process is over and reboot the system. Check if the error is still there. If yes, then proceed to the next steps. Otherwise, you may halt.
  4. Open Command Prompt with admin privilege in the same manner. 
  5. Provide the following commands and press Enter after entering commands one by one.
  1. Dism/Online/Cleanup-Image/CheckHealth.
  2. Dism/Online/Cleanup-Image/ScanHealth.
  3. Dism/Online/Cleanup-Image/RestoreHealth.
  4. Wait until the process completes. Restart your system after saving every change.

Launch Windows Defender. Double-check if the error resolves after all these scans.

Fix 6: Launch Windows Update Troubleshooter

Launch Windows Update Troubleshooter

Windows Troubleshooter works miracle sometimes when no other fixes work on your system. You have to run Windows update troubleshooter to overcome this error on Windows Defender. Go through the following steps.

  1. Head towards the Start menu of your system. You have to use the search bar to find out the troubleshooter.
  2. Type ‘troubleshooting’ and click on the Troubleshooting option from the results.
  3. Choose View All from the left pane of the launch window. 
  4. Select the Windows App Store from the list of options.
  5. Next, you have to follow the instructions from the screen to run the troubleshooter.

Restart your computer and check if you can notice the error, furthermore.

Fix 7: Opt for a Windows Update

Opt for a Windows Update

When all the above fixes are not working for your system, then you can use this fix. Check if your Windows operating system needs an update. Windows Defender can malfunction if your Windows is not up-to-date. 

Go through these easy steps to overcome the Windows Defender error code 0x800705b4

  1. Open the Settings app by pressing Win+I keys from the keyboard at the same time. 
  2. Opt for the Update and Security section.
  3. Choose Windows Update from the left pane. You’ll get the Advanced options under this tab. Click on it.
  4. You have to uncheck the box beside ‘Give me updates for other Microsoft products when I update Windows’. 
  5. Restart your PC. then you have to perform the update operation until you can notice the message that the device is up-to-date. 

Launch Windows Defender. If it launches without any error code then the error has been resolved already. 

Fix 8: Refresh your PC

Refresh your PC

Simply refreshing the computer may solve the error. But the refresh is quite different in the mechanism. Follow the instructions carefully for the proper working of Windows Defender.

  1. Open the Settings app and go to the Update and Security section. 
  2. Next, click on Recovery from the left pane and Get Started from the right pane.
  3. Choose the ‘Keep my files’ option.
  4. Follow each and every instruction.

Wait till the process completes and then reboot the system. Check if the error persists after running the Windows Defender.

Thus, here we have discussed all the possible ways to eradicate this particular Windows Defender error code 0x800705b4