This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(128, 8%, 22%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EA%3C/text%3E%3C/svg%3E)
I recently updated Windows 8 to Windows 8.1. Windows Defender had been on in Windows 8 and even after the update to 8.1. I turned it off momentarily but have been unable to turn it back on. To my knowledge, I have no other anti-virus programs running. How can I turn it back on?
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
I am unable to launch windows defender it has been turned off by something. I don't have any other virus protection. Is there any way to turn it back on. i have gone to the start menu and tried to run it as an administrator i get an error message that something else is protecting the computer but its nothing there but window defender in the action center. I am unable to get it to work.
Thanks in advance
Thank you very much Method-1 worked for me. I was trying it from 2 days to turn it on.
I had same problem. I had a trial antivirus program that was blocking windows defender, don't know why Microsoft would allow this, but after I removed the program I was able to turn on windows defender. Instructions for turning on Windows defender is on the community web site.
I need to turn on Windows Defender for 8.1 please help me?
method 1 does not work. Get error message 577, windows could not start windows defender service.
method2 .I don't have a windows defender icon on start screen.
Windows Defender on Windows 8 - Introduction and Frequently Asked Questions
