Windows updates that refuse to install and microsoft's fix it downloads do nothing with error codes 8000FFFF, 80070026, 26.

Hi Sebastian,

The issue could be caused if any third party security software or application interfering with the Updates of your computer.

I would really appreciate if you could answer the following questions:

1. Which Microsoft Fix It did you try?

2. Have you made any recent hardware or software changes to your computer prior to the issue?

3. Did you install the Update manually?

Follow the methods below:

Method 1:

I suggest you to disable your Firewall and Anti-virus application software for temporarily to check if you are able to install the Updates properly.

Step 1:

Disable antivirus software:
http://windows.microsoft.com/en-US/windows7/Disable-antivirus-software

Important Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.

Step 2:

Turn Windows Firewall on or off:
http://windows.microsoft.com/en-US/windows7/Turn-Windows-Firewall-on-or-off

Note: Once you have done with the above steps, turn on Windows Firewall.

If you still face the same issue, then please follow the next method.

Method 2:

You need to perform a Clean Boot to prevent any conflicting third party applications from interfering with your computer and try to install one Update at a time and check.

To place the computer in a Clean Boot state, you need to follow the steps from the article mentioned below and check.

How to perform a clean boot to troubleshoot a problem in Windows Vista, Windows 7, or Windows 8:
http://support.microsoft.com/kb/929135

Note: To reset the computer to normal mode after troubleshooting, please follow “How to reset the computer to start as usual” from the above article.

Method 3:

Reset Windows update components.

How do I reset Windows Update components?

http://support.microsoft.com/kb/971058

Registry disclaimer: Important this section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

http://Windows.microsoft.com/en-US/Windows7/Back-up-the-registry

Method 4:

If you receive Windows Update error 8000FFFF, it means that there are Windows‌registry values that are blocking the update from being downloaded and installed.

You can run a troubleshooter that will automatically find and fix some common problems with Windows Update, or fix the problem manually.

 Windows Update error 8000FFFF:

http://windows.microsoft.com/en-IN/windows-vista/Windows-Update-Error-8000FFFF

Note: This also applies to Windows 7 operating system.

Disclaimer: Important this section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up the registry, click the following article number to view the article in the Microsoft Knowledge Base:

http://windows.microsoft.com/en-US/windows7/Back-up-the-registry

Let us know the status of the issue. If you need further assistance, please post back. We will be glad to help you.