Windows 8.1 and Windows 10 self-security tools Windows Defender require the latest virus library support to work. This protection becomes unreliable when you encounter Windows Defender cannot start the service.
1. Rely on Windows to solve their own
When Windows Defender cannot be automatically updated, you can discard Automatic Updates to the Windows Defender and go to system update checking instead. Through the floating panel on the right side of the desktop into the "settings → change computer settings," and then select "Update and Restore →windows update", click "Check Now" (Figure 1), you will see in the update list has a virus update definition optional, download the installation directly to solve the virus library upgrade problem.
If the above method is invalid, it may be a temporary network problem. You can try the following methods in turn.
Press the Windows +x key combination, select a command prompt (administrator), enter "net stop WuAuServ" and return, locate the SoftwareDistribution folder under the C Disk Windows folder, rename it arbitrarily, and at the command prompt (administrator The command "net start WuAuServ" is entered and executed in the window (Figure 2). Then make the system update again.
Press the "Windows +x" key combination, select Control Panel; Change the upper-right corner view to large icon, then select Troubleshoot, select system and security → use Windows update to resolve issues, and follow the prompts to resolve issues that prevent updates to Windows.
If none of the above methods are effective, try to perform the system's "pure boot" according to the following steps:
Press the "Windows +x" key combination, select Enter "Run", enter "msconfig" command and press ENTER, enter "System Configuration", select "Service", check the "Hide all Microsoft Services" option in the lower left corner, click the "Disable All" button and click the "Apply" button (Figure 3) , click the Startup tab on the right side of the Services tab, click "Open Task Manager", right-click on the list of startup items, select "Disable", disable all Startup items, close Task Manager, click "OK" in the System Configuration window, and restart the computer as prompted. Then update the system again.
2. Using external tools to solve
In addition to using the system's own automatic Update function, but also through the use of 360 security guards and other external tools to solve. Select Windows Update from the Control Panel window as not to check for updates. Next through the 360 security guard System tray icon Right-click menu, select "Killing Repair", go into the scan window and choose "Bug Repair", this can also scan out the need to update the patch module and update.
To update the system's own virus protection definition, you cannot install 360 antivirus software, the software will be installed to turn off the system's own protection software and custom upgrades.