Microsoft Defender Antivirus Definition Update (KB2267602) has taken out my Wi-Fi/Internet connection

Question

Microsoft Defender Antivirus Definition Update (KB2267602) has taken out my Wi-Fi/Internet connection

Brent Sansom 0

I had a Microsoft Defender Antivirus Definition Update (KB2267602) this morning, and this update has taken out my Wi-Fi/Internet connection; and I can't now connect to the internet because it has a conflict with the Intel Wi-Fi driver [6E AX211 160MHz]. Everything worked okay yesterday, so it has to be this update as it's the only thing that's changed on my laptop.

I have tried removing and reinstalling the driver (didn't work), and it won't uninstall the update via the 'Update History'-'Uninstall Updates' feature.

I have had VERY brief success when 'Restarting' my laptop via the 'Advanced Options'-'Advanced Startup'-'Restart Now' method, but after the Wi-Fi settings being briefly available (for about a minute), they disappear again.

I've tried to limp along via my phone's 4G, but the Bluetooth Connection has also been affected, and I can only connect via Bluetooth for very short periods of time, and it can take half an hour to establish a connection - so this isn't even a worth doing for short-term work-around.

I can't afford to do a PC Reset, as the amount of time it will take me to fully load all my work apps again isn't worth me considering (I'll lose a couple of days work-time if I have to do this - and I've already lost most of today trying to fix this problem).

I could really just do with uninstalling the Microsoft Defender Antivirus Definition Update (KB2267602).

Thanks in advance1

3 answers

Your answer

Answer 1

Clary-N 9,170 Microsoft External Staff Moderator

Hi Brent Sansom,

Thank you for reaching out to Microsoft Q&A forum. I understand how disruptive this situation is, especially when both Wi‑Fi and Bluetooth are affected and your work depends on this device.

From the symptoms you described, this looks like a software interaction that happens during normal Windows startup rather than a hardware failure. The fact that connectivity briefly returns after an Advanced Startup restart is an important clue and helps narrow where the problem is occurring.

Below are the next steps I recommend:

Step 1 – Temporarily turn off Microsoft Defender real‑time protection

Open Windows Security from the Start menu.
Select Virus & threat protection.
Click Manage settings.
Turn Real‑time protection Off.
Wait a few seconds and check whether Wi‑Fi and Bluetooth return.

This checks whether a background security component that loads during startup is interfering with network initialization.

Step 2 – Remove the currently installed Defender security definitions

Right‑click Start and choose Command Prompt (Admin).

Paste the command below exactly as shown and press Enter:

   %ProgramFiles%\Windows Defender\MpCmdRun.exe -RemoveDefinitions -All

Once the command completes, restart the laptop normally.

This clears the active Defender definitions so Windows can start using the previous set. Microsoft Defender itself is not removed.

Step 3 – Keep connectivity stable

After restart, confirm that Wi‑Fi and Bluetooth remain available.
If they do, avoid manually checking for updates straight away.
If real‑time protection turns itself back on and connectivity drops again, you can temporarily turn it off while continuing your work.

Step 4 – Clean reinstall the Intel Wi‑Fi driver

Press Windows + X > Device Manager.
Expand Network adapters.
Right‑click Intel Wi‑Fi 6E AX211 > Uninstall device.
Check Delete the driver software for this device and confirm.
Restart the laptop.
Install the latest Wi‑Fi driver directly from Intel’s website.

Please keep me posted on how it goes and feel free to reach out if you need any further assistance. I'm here to help.

If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Brent Sansom 0 Reputation points

2026-02-10T07:32:19.1233333+00:00

After 8 hours of frustration, I have tried the first 5 proposed solutions (and managing to download updates, one of which was for the update (KB2267602) that caused the problem - so I was hopeful, took ages because I had no internet connection and a bad Bluetooth connection because the update affected that too (eventually managed it, but it took me ages to download via my mobile phone).

So, how do I contact Microsoft support to get them to fix this problem caused by the update?
Brent Sansom 0 Reputation points

2026-02-10T07:54:35.2466667+00:00

Hi Clary,

Sorry - only just seen your reply - I'm having to work on an old (creaky) laptop for an internet connection so that I can actually communicate in the forum.

Unfortunately, I can't even get past Step 1, as my Virus & threat protection menu does not have a 'Manage settings' option, so I can't turn Real‑time protection Off; I've tried looking/searching for this function, but I can't locate where it is and so am stuck.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-10T08:04:00.2166667+00:00

Hi Brent Sansom,

Would you mind sending me a screenshot of your current Windows Security settings screen please?
Brent Sansom 0 Reputation points

2026-02-10T10:03:39.9133333+00:00

This is all that's on the Virus & threat protection menu...
Brent Sansom 0 Reputation points

2026-02-10T10:32:18.9766667+00:00

This is the main Security menu - just in case you need this too
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-11T08:25:48.3033333+00:00

Hi Brent Sansom,

Thank you for the screenshot, that’s very helpful.

From what you’re seeing, Windows Defender is not the active antivirus on your system. Avast Antivirus is currently managing virus and threat protection, which is why the “Manage settings” option for Microsoft Defender does not appear.

When a third‑party antivirus (like Avast) is installed and active, Windows automatically disables Microsoft Defender’s real‑time protection controls.

If you prefer to continue using Avast, you can temporarily disable it for testing purposes and then proceed with the next step.

To do this, open the Avast app from the Windows Security screen, locate Core Shields (or Real‑Time Protection), and turn it off temporarily. Once testing is complete, you can re‑enable it.

*Disclaimer: Temporarily turn off antivirus protection. However, keep in mind that if you do so, your device may be vulnerable to threats. So please turn it on immediately once issue fixed.
Please give it a try and keep me updated.
Brent Sansom 0 Reputation points

2026-02-12T08:08:49.7033333+00:00

Unfortunately, that command did not work (Program is not recognised) - I tried the command without spaces too in case this was causing an issue, but got the same response - see the attached screenshot.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-12T09:18:39.7633333+00:00
Hi Brent Sansom,

Please try again using the command below (ensure Command Prompt is opened as Administrator):

"C:\Program Files\Windows Defender\MpCmdRun.exe" -RemoveDefinitions -All

The quotation marks are required because the file path contains spaces.

Let me know if this works or if you still see the error.
Brent Sansom 0 Reputation points

2026-02-12T17:34:14.29+00:00

Hi Clary,

Still not getting anywhere with the Command Prompt (as Administrator).

But I'm now getting the message "The system cannot find the path specified." instead of "Program not recognised".
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-13T02:51:33.4233333+00:00

Hi Brent Sansom,

Thanks for the update.

“The system cannot find the path specified” means Windows cannot locate MpCmdRun.exe at the path being used.

At this stage, the recommended next step is a clean reinstall of the Intel Wi‑Fi driver, as this often resolves startup initialization conflicts without needing Defender command‑line changes.
Please give it a try and keep me updated.
Brent Sansom 0 Reputation points

2026-02-13T07:53:21.75+00:00

Hi Clary,

I have done this before (completely removed it, and then re-downloaded the specific Intel driver) as this was advertised as a potential fix - it didn't work then. But I will try this in conjunction with switching Avast off, and see where that gets me.
Brent Sansom 0 Reputation points

2026-02-13T09:09:19.3+00:00

Hi Clary,

I've re-installed the Intel driver again, but it's still flagging up as having a problem.
Brent Sansom 0 Reputation points

2026-02-13T10:34:39.4033333+00:00

Hi Clary,

My last reply was deleted for some reason? It was an screenshot image showing the Intel Wi-Fi driver having an exclamation/warning on it - showing the the re-install of the driver did not correct the problem.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-14T08:52:58.52+00:00

Hi Brent Sansom,

Thanks for confirming the results of your testing.

Since the issue persists after a clean reinstall of the Intel Wi‑Fi driver and with third‑party security software disabled, this may indicate a deeper Windows system‑level conflict rather than a driver installation problem.

At this stage, the recommended and most reliable next step is to perform a Windows in‑place upgrade. This process refreshes core Windows components while keeping your files, applications, and settings intact, and is effective at resolving underlying corruption or service conflicts that cannot be corrected through driver reinstallation alone.

*Disclaimer: Let’s try performing an in-place install or in-place upgrade which will refresh your Windows files and operating system without removing files or applications. That being said, we always recommend that if you have important data, you should back it up before making large system changes. If you want to back up your data first, please do so. Once you are done backing up, you can follow the steps in the following guides: How to run In-place upgrade in Windows 11 - Microsoft Q&A

Please proceed with the in‑place upgrade then once completed, reinstall the Intel Wi‑Fi driver and confirm whether the adapter initializes correctly.

If the issue persists after the in‑place upgrade, we can reassess next steps based on the results.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-16T02:21:05.2366667+00:00

Hi Brent Sansom,

I have not heard from you for a couple of days.

Please let me know if there is anything I can help by leaving your comment down here.
Brent Sansom 0 Reputation points

2026-02-17T08:22:02.7266667+00:00

Hi Clary,

Apologies for the delay in update - as I had no connection to the internet, and no RJ45 socket for a hard-wire connection to the internet in order to perform this recommendation of an in-place upgrade, I had to go out an buy a docking station (and also a new laptop - as I'm self-employed and couldn't work properly last week because of the Windows update conflict - but I still want my old laptop fixing as it's an expensive one).

So - after completing the steps of your recommendation, I can confirm that the problem still exists. I have also uninstalled my Avast and tried the original recommended steps - none of which worked.

And, as I have an internet connection via my new docking station, I also installed all the new Windows Updates (2 were Security Updates) which I had hoped might help; which they didn't.

So, what would be the next steps?
Brent Sansom 0 Reputation points

2026-02-17T13:21:29.1233333+00:00

Hi again Clary,

So, an update on the previous comment that I left 5 hours ago:- I've just gone to get some files from my old laptop, to transfer to my new one, and when I opened the lid up, bringing the laptop out of its sleep-mode, I found that the Wi-Fi just started to work again (hooray)!

I had done nothing with the old laptop since this morning - I'd had it open for a few hours this morning, and not connected to the new docking station (and it had no WiFi at this point) before closing the lid and parking it for a while - so, whether it's just had time to work through its processes, but it just started working when I opened it up again.

Now I'm not sure if I should reload antivirus software in case this had anything to do with the driver conflict? What do you think, would it be safe to reload antivirus software?

Thanks.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-18T01:43:38.48+00:00
Hi Brent Sansom,

Thanks for the update.

It’s good to hear that Wi‑Fi is now working again after the laptop resumed from sleep. This points more toward a software or driver state issue rather than a hardware fault.

It is safe to reinstall your antivirus, as long as you use the latest version from the vendor’s website. After reinstalling, please monitor the Wi‑Fi through a restart and sleep/wake cycle.

If the issue returns, it’s likely a software conflict and we can take the next steps from there.

If it remains stable, no further action is needed for now.

Please let me know how it behaves after the antivirus reinstall.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-19T03:29:47.0033333+00:00

Hi Brent Sansom,

Have you had a chance to check my answer yet?

Please do keep me updated.
Brent Sansom 0 Reputation points

2026-02-20T13:10:43.6666667+00:00

Hi Clary,

I thought that I'd give it a couple of days before I installed the anti-virus software (just to be sure that the WiFi driver was stable).

But before I got to install the anti-virus software, unfortunately, there was another Defender update that came in and has taken the WiFi out again (see the attached screenshot image of the update); and again, it's the KB2267602 update that has done the damage.

What do you recommend?
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-21T08:12:24.7366667+00:00

Hi Brent Sansom,

Thanks for the screenshots.

From what you shared, the Wi‑Fi drop is happening due to the Defender update (KB2267602), not the antivirus install.

We have two options. First, we try to stabilise the system by installing the correct Wi‑Fi driver from the manufacturer and preventing Windows from replacing it. This usually resolves it without reinstalling Windows.

If the issue keeps coming back, the clean solution is to back up your files and do a clean Windows install. This removes the corrupted update state and gives the most reliable long‑term result.

Let me know which option you’d like to proceed with and I’ll help you through it.
Clary-N 9,170 Reputation points Microsoft External Staff Moderator

2026-02-24T09:16:36.0833333+00:00

Hi Brent Sansom,

I have not heard from you for a couple of days.

Please let me know if there is anything I can help by leaving your comment down here.

Answer 2

kagiyama yutaka 1,245

kb2267602 kinda threw the ax211 off… I’m not totally sure, but clearing the defs w/ mpcmdrun RemoveDefinitions All got the nic to at least show up again on my side. after that I just pushed the older offline defs so the sig engine stops wrestling the fw during bring‑up… nothing fancy. if the radio still drops on boot, turning off fast‑startup once usually forces a clean cold init — ax211 tends to behave after that, at least in my exp...

Answer 3

It seems that you're experiencing connectivity issues after a Microsoft Defender Antivirus Definition Update (KB2267602), which may have caused a conflict with your Intel Wi-Fi driver. Here are some steps you can take to troubleshoot the issue:

Check for Additional Updates: Sometimes, subsequent updates can resolve issues caused by previous ones. Check Windows Update for any new updates that might address this problem.
Network Troubleshooter: Use the built-in network troubleshooter. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Internet Connections and run the troubleshooter.
Reinstall Wi-Fi Driver: Since you've already attempted to reinstall the driver without success, ensure that you are using the latest driver version from the Intel website. Sometimes, rolling back to a previous version of the driver can also help.
Disable Fast Startup: Disabling Fast Startup can sometimes resolve connectivity issues. You can do this by going to Control Panel > Power Options > Choose what the power buttons do > Change settings that are currently unavailable > Uncheck "Turn on fast startup".
System Restore: If the issue persists, consider using System Restore to revert your system to a point before the update was installed. This will not affect your personal files but will remove any applications or updates installed after the restore point.
Contact Support: If none of the above solutions work, it may be best to contact Microsoft Support for further assistance.

Unfortunately, uninstalling specific Microsoft Defender updates directly through the interface may not always be possible, especially if they are critical updates.

References:

Share via

Microsoft Defender Antivirus Definition Update (KB2267602) has taken out my Wi-Fi/Internet connection

3 answers

Your answer