You may get this error if some third-party antivirus conflict with Windows Update. To fix this problem, use the following methods in the order in which they are listed. After each method, check if problem is fixed. If the problem is not fixed, try the next
method.
Method 1: if you are using any third party antivirus program. I would suggest you to temporarily disable it and check.
Warning: 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.
Method 2: I would suggest you to run the Windows update troubleshooter from this link or manually follow the instructions given in this link to try to fix the Windows update issue first.
If the troubleshooter as well as the steps do not help, try to run the DISM commands and then try check if you are able to install the Windows update. (Install only 3 to 5 updates at once instead of installing all the updates altogether)
1. Type Command prompt in the Search Charms, right click on it and select Run as Administrator.
2. Type the following commands. Press Enter after each command.
DISM.exe /Online /Cleanup-image /Scanhealth
DISM.exe /Online /Cleanup-image /Restorehealth
3. Close the command prompt, and then run Windows Update again.
Once the Windows updates are installed Successfully, restart the computer and check if Windows 8.1 update is available. Make sure the update KB 2871389 is installed successfully on the computer. Please refer to
http://support.microsoft.com/kb/2871389/en-us
