Windows Defender is an anti-spyware application that detects and eliminates offending programs. Defender is minimally invasive, while offering real-time security against virtual threats. Occasionally, an attempt to update Windows Defender can result in a 0x80070002 error.
Upon bootup, the following message may appear, "A problem is preventing Windows from accurately checking the license for this computer. Error code: 0x80070002." The problem isn't limited to Windows Defender: For example, Windows Service Pack updates resulting in the message "An internal error occurred while installing the service pack" or "Installation was not successful" are also signs of a system experiencing error 0x80070002.
According to Microsoft, error 0X80070002 is related to changes made via Windows Update. When update files are incomplete or corrupted, the computer will register an error. The error may also be triggered when a change is made to the default security program or to the system drive letter.
Users may be able to correct this error by deleting the update or restoring the computer to the point before the changes were made. Microsoft then suggests downloading and reinstalling the updates. If reinstallation does not work, the error may be resolved by changing the drive letter or reinstating the previous security settings.