Q. I keep getting Windows Update “failed” error messages with a long number (0x80070020) when I try to install Microsoft’s patches for Windows 10. Clicking the Retry button leads again to failure. What does this number mean and why can’t this system update itself properly?
A. The numbered error codes you see when Windows alerts you to an update failure or system issue and indicate a specific type of problem. Microsoft’s support site has a page called “Fix Windows Update issues” that guides you through diagnosing the problem and offers to run software tools like the Windows Update Troubleshooter in an attempt to resolve those issues.
In the specific case of Error 0x80070020, Windows Update is complaining that another program interfered when it tried to install the new software updates, so it failed to complete the task. The most likely culprits are antivirus programs or other security software that runs in the background patrolling for malicious code.
Try turning off any security applications you have installed on the computer and then run Windows Update again to see if it can get through the installation. If you successfully make it through the update process, turn on your security software again and move on.
If you do not use a security application or think a different kind of program is tangling with Windows Update, Microsoft recommends performing a “clean boot” of the system, in which you prepare the PC to start up with a very basic set of drivers and background services so third-party programs can’t get in the way. The company’s support site has step-by-step instructions for doing a clean boot of Windows 10 and earlier versions of the software.
For those having problems installing last month’s Windows 10 April 2018 Update, the Windows Central site (which is not affiliated with Microsoft), has a helpful guide to dealing with common issues that have cropped up. The Windows Club, another independent site, also has a running list of user-reported problems and known fixes for troubles caused by the update. Reading up on the Windows community sites before you attempt to install major upgrades can also be helpful if you want to know what problems others have encountered and what to expect.
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