What is FirewallAPI.dll & How to Fix its Errors

Using a DLL fixer tool is very effective in this situation

Reading time icon 4 min. read

Readers help support Windows Report. We may get a commission if you buy through our links. Tooltip Icon

Read our disclosure page to find out how can you help Windows Report sustain the editorial team Read more

Key notes

  • The FirewallAPI.dll is also known as Windows Defender Firewall API and it’s a legitimate file made by Microsoft.
  • However, many of our readers reported many errors related to this DLL caused by missing or corrupted files.
How to fix firewallapi.dll errors

FirewallAPI.dll is a DLL made by Microsoft and it’s known as the Windows Defender Firewall API file. It is mostly used by Microsoft Office Access 2010 but many of our readers complained about the multiple errors caused by FirewallAPI.dll. Here, you will find out all about this DLL file and how to fix its errors.

What is FirewallAPI.dll and what errors is it causing?

As we mentioned above, FirewallAPI.dll is a DLL file that stores information and instructions for executable (EXE) files. It was created so that multiple apps have the right memory allocation and make your PC more efficient when running them.

However, FirewallAPI.dll is missing, gets corrupted, and produces errors such as the ones listed below:

  • FirewallAPI.dll could not be found.
  • Cannot register FirewallAPI.dll.
  • Failed to load FirewallAPI.dll.
  • The file FirewallAPI.dll is missing or corrupt.
  • Access Violation at address – FirewallAPI.dll.
  • Cannot find C:\Windows\Temp\527D94AF-D053-4381-B105-0D815D53791E\wow64_networking-mpssvc-svc_31bf3856ad364e35_10.0.16299.967_none_b1e2101e67140208\FirewallAPI.dll.
  • Cannot start Microsoft Office Access 2010. A required component is missing: FirewallAPI.dll. Please install Microsoft Office Access 2010 again.
  • The application has failed to start because FirewallAPI.dll was not found.
  • This application failed to start because FirewallAPI.dll was not found.
  • Our readers also encountered the errors FirewallAPI.dll 80201, 80202, 80204, 80205, and 80206.

All of these errors are caused by missing or corrupt FirewallAPI.dll. The causes for this problem range from accidental deletion, virus, or malware infection to corrupt system files and apps that are using the file.

How do I fix FirewallAPI.dll errors?

Before going to more complicated solutions, perform the following prerequisite methods:

  • Make sure to install all the OS and software updates possible, especially for the affected app.
  • Try reinstalling the app that triggers the error, such as Microsoft Office Access 2010.

If these workarounds were not efficient, start performing the solutions below.

1. Use a DLL fixer

Manually reinstalling the FirewallAPI.dll is a risky endeavor so, in this case, we strongly recommend using a DLL fixer.

2. Run an SFC scan

  1. Click the Search button on your taskbar, type cmd, and select Run as administrator from the results.
  2. Now, type or paste the following command and press Enter to run it: sfc /scannow
  3. Wait for the scan to finish, then restart your PC and see if the FirewallAPI.dll error is fixed.

System File Checker is an effective Windows tool that detects and repairs the corrupt system file so it can be very efficient for fixing the FirewallAPI.dll error.

3. Perform a full virus scan

  1. Click the Search icon, type windows security, and open the app from the results.
  2. Select Virus & threat protection.
  3. Next, select Scan options.
  4. Check the Full scan box and hit the Scan now button below.

If your PC is infected with a virus or malware, they could mess with the system files and FirewallAPI.dll.

Scanning your PC using Windows Defender might be effective, but we recommend scanning your system with a more powerful third-party antivirus.

4. Perform System Restore

Note icon NOTE
This solution will turn your system back in time so if you installed any software after that instance, it will no longer be available.
  1. Click the Search icon, type create a restore point, and click the app from the results.
  2. Now, click on the System Restore button.
  3. Next, select a restore point that has a date before this problem happened and hit Next.
  4. Acknowledge your choice to perform the restoration.

System Restore is like a time capsule for your PC and will turn back your system to a previous point in time before the FirewallAPI.dll error ever happened so it will fix the problem.

These are the most effective solutions to fix FirewallAPI.dll errors and we hope that your PC and apps are functioning correctly now.

However, if the situation is more serious, you will need to reset your Windows 11 to factory settings.

For any questions or other viable solutions, let us know about them in the comments section below.

More about the topics: DLL errors, DLL issues