Forum Discussion
"Turn on Virus Protection" Notification appears after the latest update
So after the latest Windows 11 update I constantly get a single notification from Windows Defender claiming that it was turned off and suggesting to "Turn on Virus Protection". Fun fact is that Defender keeps working all the time and never turns off. Another fun fact is that the notification appears at the same exact time, 4m13sec after logging into account (judging by task manager uptime timer). I've heard a similar story from another user experiencing the same issue after latest update, but for him the notification appears at 4m23sec.
I contacted support and they said that they might require multiple feedbacks on this issue from different users to confirm that it's a bug. While my PC was checked by Microsoft support team member and he confirmed that there's no issue with my system. Everything runs perfectly fine and working as it should.
From the side it looks like it's some scheduled event bug, however upon checking task scheduler there was nothing to trigger this notification. As well as event manager shows no visible signs of critical errors on that matter (or at least I don't see any).
It's extremely concerning to me, cause it's the first issue related to Windows Security which happened to me since my first day of using Windows 11. And there's no trace of it, so basically it's unable to identify the source of this bug.
Reinstalling system helped for a while, but after several hours a few minor security updates were installed, and the notification came back. Like i said, it appears only once after each account log in. If my PC goes to sleep, I can wake it up as many times as I want and it won't show it ever again.
Can anyone confirm the same weird behavior after the latest updates? If so, is anyone willing to send a feedback?
This is a known issue reported widely in forums. It might be caused by July Cumulative Update Preview or August Cumulative Updates. We may expect a fix from September Cumulative Updates.
UPDATE (18/09/2026): This issue has been resolved by Microsoft. If you're affected, pls install or update the Microsoft Defender Antivirus update (version 4.18.26080.4) update:
https://learn.microsoft.com/en-us/windows/release-health/resolved-issues-windows-11-25H2#august-2026
You can also refer detailed fix here:
https://www.kapilarya.com/turn-on-virus-protection-keeps-popping-up-in-windows-11
Hope this helps!
Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.
20 Replies
Also happening on my two machines running W11 25H2. Issue first appeared around end of August for me - after holidays. I got scared and formatted one of them only to discover that the issue persisted even on a cleanly installed OS - which led me here. Disappointed once again by MS rolling out breaking updates.
Windows Defender “turned off” notification on every boot — fix
If Microsoft Defender has recently started showing a notification at every Windows startup saying that antivirus/Defender is turned off, despite Defender eventually showing as enabled, a recent Defender platform update may be responsible.
In my case, the problem started after a recent Windows update.
My Defender platform versions were:
4.18.26080.4 — problem occurred
↓
4.18.26080.3 — problem still occurred
↓
4.18.25080.5 — problem completely disappearedI rolled the Defender platform back using PowerShell as Administrator:
$mp = Get-ChildItem "$env:ProgramData\Microsoft\Windows Defender\Platform" -Directory | Sort-Object Name -Descending | Select-Object -First 1 & "$($mp.FullName)\MpCmdRun.exe" -RevertPlatform
Running the rollback again took me from 4.18.26080.3 → 4.18.25080.5.
After rebooting on 4.18.25080.5, the annoying startup notification was completely gone.
If you're experiencing the same issue, check your Defender platform version with:
(Get-MpComputerStatus).AMProductVersion
Important: this is a workaround for the specific startup notification issue I experienced, not a recommendation to permanently disable or leave Defender outdated. A later Microsoft Defender platform update may contain a fix.
Hopefully this saves someone else the headache of thinking their antivirus is actually being disabled every time Windows boots.
Same problem. I was wonder what is going on and how to solve it.
Just started in last few days. I power the computer off when not in use and upon restart I get the exact same message after roughly the same period of time. I tried to return to an earlier restore point, this did not solve anything. Brand new computer not 6 months old. Win 11, current updates, everything was fine 3 days ago.
This is a known issue reported widely in forums. It might be caused by July Cumulative Update Preview or August Cumulative Updates. We may expect a fix from September Cumulative Updates.
UPDATE (18/09/2026): This issue has been resolved by Microsoft. If you're affected, pls install or update the Microsoft Defender Antivirus update (version 4.18.26080.4) update:
https://learn.microsoft.com/en-us/windows/release-health/resolved-issues-windows-11-25H2#august-2026
You can also refer detailed fix here:
https://www.kapilarya.com/turn-on-virus-protection-keeps-popping-up-in-windows-11
Hope this helps!
Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.
A few minuets after I log-On I get a notification showing a pop-up asking me to turn on virus protection.
I was having this issue: "Controlled folder access" switched off under "Ransomware protection" So the info in this thread was really helpful in eventually finding (my) real cause. Clicking the pop-up just takes you to the virus and protection instead of the exact toggle that's switched off. Just vague enough to look like a bug to me.
TLDR: Check (every) option under "Virus & Threat protection" because any toggle off will trigger the generic pop-up we're getting. But it's not smart enough to take us to the exact toggle that's switched off.I will try it, thanks. Weird it isn't on by default, as even formatting the drive and fresh install made the bug appear again..
after isuese whit DEFENDER to cant scan update its fixed but back problem notification its just backrool update its dont know fix scann .
I’m also facing a similar issue. After restarting my system, Windows Defender keeps showing a pop-up asking me to turn on virus protection, even though the virus protection is already enabled and working.
Not sure why Defender is showing this warning after every restart. Any idea why this is happening?
I’m also facing a similar issue. After restarting my system, Windows Defender keeps showing a pop-up asking me to turn on virus protection, even though the virus protection is already enabled and working.
Not sure why Defender is showing this warning after every restart. Any idea why this is happening?
