If you have AVG antivirus installed you cannot access any area of windows defender. You failed to mention this before. Windows 8 and 8.1 automatically deactivate windows defender if you install another anti-virus program. If you uninstall the AVG you should be able to access the windows defender application. I did exactly that, I uninstalled AVG and MagicDisc and it still didn't work, but still, thank you.
http://www.tomshardware.com/answers/id-2225882/turn-windows-defender-back.html
Unable to turn on Windows Defender. Scenario 1: On of the most common behavior of Windows Defender is that if it detects a third-party antivirus software, then Windows Defender will shut itself off. Windows is designed to detect the presence of security software installed, and we often we get to see the notification in the Action Center.
http://www.thewindowsclub.com/unable-to-turn-on-windows-defender
If you have Windows 10, you’ll get the latest antivirus protection with Windows Defender. When you start up Windows 10 for the first time, Windows Defender is on and actively helping to protect your PC by scanning for malware (malicious software), viruses, and security threats. Windows Defender uses real-time protection to scan everything you download or run on your PC.
https://support.microsoft.com/en-us/help/17464/windows-defender-help-protect-computer
Windows 8 and 8.1 automatically deactivate windows defender if you install another anti-virus program. If you uninstall the AVG you should be able to access the windows defender application. Jul 19, 2014, 4:57 PM. I did exactly that, I uninstalled AVG and MagicDisc and it still didn't work, but still, thank you.
http://www.tomshardware.com/answers/id-2225882/turn-windows-defender-back.html
CAN'T TURN ON WINDOWS DEFENDER. Windows Defender is turned off. When I click on the “Turn On now” button. Windows Security Centre searches for definitions but after a short period I. receive message to say “ Security Centre Can’t update definitions for Windows. Defender”. My operating system is Vista Home Premium.
https://www.vistax64.com/vista-security/77521-cant-turn-windows-defender.html
Turn Windows Defender real-time protection on or off. 1  Select the Start button, then select Settings > Update & Security. 2  Select Windows Defender, then turn Real-time protection on or off.
https://support.microsoft.com/en-us/help/17464/windows-defender-help-protect-computer
Windows Defender turned off (in Windows 10) Can't turn it on. #1. I have had Windows 10, 64 bit since the end of August and recently I noticed that Windows Defender is turned off and will not allow me to turn it on. It does this even if I run as administrator.
https://www.bleepingcomputer.com/forums/t/592660/windows-defender-turned-off-in-windows-10-cant-turn-it-on/
Windows Defender is turned off or not working. You may receive a message: Windows Defender has been turned off, and it isn’t monitoring your computer. If you have another antivirus software installed, it will turn off Windows Defender.
http://www.thewindowsclub.com/windows-defender-is-turned-off
#3. I had the same issue when trying to turn Norton 360 off to use my companies VPN which checks anti virus software. The VPN is compatible with Defender but not 360 (yet). I was able to run the VPN on a machine that only had Defender on it. Alienware 18 Intel Core i7 4810 QM 16GB DDR3.
https://www.bleepingcomputer.com/forums/t/592660/windows-defender-turned-off-in-windows-10-cant-turn-it-on/
Ensure that the Windows Defender service is started and set to Automatic. 6] If Windows Defender Service (WinDefend) or Windows Defender Network Inspection Service (WdNisSvc) of Windows Defender keeps stopping, turning off or could not start, Re-register the following dll files and see if it helps you.
http://www.thewindowsclub.com/windows-defender-is-turned-off
cannot turn windows defender on
On of the most common behavior of Windows Defender is that if it detects a third-party antivirus software, then Windows Defender will shut itself off. Windows is designed to detect the presence of security software installed, and we often we get to see the notification in the Action Center.