Can't connect to any VPN after today's Windows Updates / Windows 11

Carlo Mendoza 151

I'm now getting this error trying to connect to VPN on Windows 11: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

I've noticed this on 2 Windows 11 laptops (one personal and another for work). Both have been updated today and no longer able to connect to a couple VPNs.

2022-01 Cumulative Update for Windows 11 for x64-based Systems (KB5009566)

Anyone else? Anyone know how to fix it other than uninstalling the update?

Carlo Mendoza 151 Reputation points

2022-01-12T07:26:34.27+00:00

It looks like others are experiencing this issue: https://techcommunity.microsoft.com/t5/report-an-issue/windows-11-update-kb5009566-inhibits-vpn-connection/m-p/3057844
Thunder Solutions 51 Reputation points

2022-01-12T14:54:27.927+00:00

So today I was near to shot my head, same problem with windows 10 uninstall kb5009543 and everything will work again. First I uninstall kb5008876 but no effect, then....
Anderson Wavrik 21 Reputation points

2022-01-12T23:26:40.79+00:00

This is happening not only in Windows 11 but in Windows 10 too. How can i fix this or downgrade?
Birdman .....Annoyed 6 Reputation points

2022-01-13T00:30:28.05+00:00

How did you uninstall 5009543 ??

I try and it tells me its a required update and cannot be uninstalled.
remoteitguy44 36 Reputation points

2022-01-13T01:38:55.127+00:00

Thanks for the post. Same problem with Windows 10. I removed kb5009543 and my VPNs started to work again. It cost me a very important meeting as I was fighting with my laptop trying to get things functioning. The fact that Microsoft still pushes out updates like this after well over 20 years of patch screw-ups like this is not surprising.
Robert Pearman 36 Reputation points

2022-01-13T11:57:14.127+00:00

Just to say I had to remove KB5009543 & 2 other updates before the VPN would connect.
Becca Rose 1 Reputation point

2022-01-13T13:19:08.12+00:00

This worked for me, removed kb5009543 on windows 10 and rebooted and my VPN reconnected immediately. Pausing updates for a few weeks so Microsoft can repair this update....
Ketan Tejani 1 Reputation point

2022-01-13T13:26:03.737+00:00

Thanks for this post - I got same isssue and your post saved me from agonizing pain I would have gone through.
Howard Beattie 1 Reputation point

2022-01-13T15:34:11.977+00:00

Robert,

What were the other 2 updates you uninstalled and are you running Windows 10 or 11.

Cheers!
H
Gabor Szucs 6 Reputation points

2022-01-13T16:34:28.83+00:00

After a day of figuring out why the L2TP/IPSec PSK connection not working (till yesterday morning), I found the same: I had to remove KB5009543!
Unfortunatelly I can't hide this upgrade (or any other) from the update list like I did in Win7 for example.

BUT!I found this:
https://tweaks.com/windows/67132/how-to-block-specific-driver-or-patch-updates-in-windows-10/

It works!
Guillermo Delgadillo 1 Reputation point

2022-01-13T17:26:05.727+00:00

THANK YOU!!!!
this finally worked and the VPN is connecting again, had to go through lots of hours researching just to find Microsoft singing Ups I did it again, GRRRR
David B 1 Reputation point

2022-01-14T09:18:24.773+00:00

Solved VPN Issue. THANK YOU!
Igor Valsichi 1 Reputation point

2022-01-14T11:24:57.143+00:00

it seems to affect AZURE SSTP Vpns as AZURE AD uses do authenticate users
Igor Valsichi 1 Reputation point

2022-01-14T11:28:09.297+00:00

Thank you MS!

MS is giving us an opportunity to make money (lol)
Giovanni 1 Reputation point

2022-01-14T11:37:50.387+00:00

Also experiencing this problem. When can we typically expect a fix for this from Microsoft? Thanks
remoteitguy44 36 Reputation points

2022-01-14T12:02:37.217+00:00

This KB article has been replaced by a useless FAQ that says your only choice is to suspend updates for 7 days.
Debbie Balser 1 Reputation point

2022-01-14T19:34:23.283+00:00

I had the same problem , had to to uninstal the update to get VPN working lost 2 days of work !!
Geeves 16 Reputation points

2022-01-16T21:54:11.663+00:00

Windows 10: wusa /uninstall /kb:5009543
Windows 11: wusa /uninstall /kb:5009566
IkhsanC 11 Reputation points

2022-01-17T03:23:04.49+00:00
TRY to use this

OPEN POWERSHELL (ADMINISTRATOR)

TYPE> WMIC QFE LIST BRIEF /FORMAT:TABLE

TYPE> WUSA /UNINSTALL /KB:(NUMBER)
IkhsanC 11 Reputation points

2022-01-17T03:24:03.9+00:00
TRY THIS:

OPEN POWERSHELL (ADMINISTRATOR)

TYPE> WMIC QFE LIST BRIEF /FORMAT:TABLE

TYPE> WUSA /UNINSTALL /KB:(NUMBER)
Er Mandhon 1 Reputation point

2022-01-17T04:38:09.07+00:00

trims dude, worked
Boye Madsen 1 Reputation point

2022-01-17T05:41:12.563+00:00

Hi

I g’et the same answer Update can’t be uninstalled. But thank you for the answer.
IT Saunders 6 Reputation points

2022-01-18T14:14:02.29+00:00

Thank you! This worked. Also for anyone wondering how to uninstall the windows update, you can follow this guide if you don't want to use powershell: https://www.tomsguide.com/how-to/how-to-uninstall-a-windows-10-update
TZ 76 Reputation points

2022-01-18T16:21:31.443+00:00

not for W10
Marcus Hammer 1 Reputation point

2022-01-19T09:55:29.817+00:00

Removing 5009543 helped out for me. L2TP/IPSEC works again.

I have reported to Microsoft through Feedback hub and I think all that experience this should do the same to get MS's attention.

We have 30 computers at our company suffering from this!

Feedbackhub:
https://support.microsoft.com/en-us/windows/send-feedback-to-microsoft-with-the-feedback-hub-app-f59187f8-8739-22d6-ba93-f66612949332
Balazs 1 Reputation point

2022-01-21T08:32:47.673+00:00

Dear Everyone,
I use windows 10 and I experienced after installed windows10.0-kb5010793 patch not fully solved the problem…
I can connect to VPN from home network but if I use a mobil hotspot wifi then I can't connect to VPN and I get similar error message.
Is there problem anyone? Anyone know how to fix it? The uninstalling could't solve this problem.
Thank you in advance for your help.
Ethan 1 Reputation point

2022-02-01T19:29:17.483+00:00

I am setting up a new computer that we just purchased and having this same issue, so there isn't a previous update to roll back to. Is there another solution besides uninstalling KB5009566?
Wayne Schoeman 1 Reputation point

2022-02-02T15:15:09.583+00:00

Just change the type to pptp

34 answers

Julius Hardt 36 Reputation points

2022-01-12T07:53:04.52+00:00

I experienced this same issue with exactly the same error message on all of my Win 11 machines, too (using an L2TP VPN with a pre-shared key and PAP). After uninstalling KB5009566, I could connect successfully again, so it is likely that the issue is indeed related to the update. (Of course, uninstalling security updates is not a good idea, this was just for testing purposes.)

If you want to record the problem or upvote it, here is a Feedback Hub item you may link to: https://aka.ms/AAffr20
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7 people found this answer helpful.

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Reza-Ameri 16,831 Reputation points

2022-01-14T16:06:43.767+00:00

Microsoft is aware of this issue and working on a fix for this issue as a workaround you may disable Vendor ID in the server side for your VPN (in case this option is available) or uninstall the update.
Here is the reference from the Microsoft:
https://support.microsoft.com/en-us/topic/january-11-2022-kb5009566-os-build-22000-434-eee797fa-5ee3-4501-aeec-db3bc73b2c7b
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Reza-Ameri 16,831 Reputation points

2022-01-12T16:15:25.05+00:00

Thank you for reporting this issue and like the discussion in this community, I believe this is a bug, so make sure open start and search for feedback and open the Feedback Hub app and report this issue.
As workaround, you may uninstall the update and restart your PC.
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Birdman .....Annoyed 6 Reputation points

2022-01-13T00:25:16.8+00:00

So how do I uninstall this for 150 users?

Windows 10 will not allow for uninstall of 5009543. It is apparently necessary for your system according to the MS overlords

Reza-Ameri 16,831 Reputation points

2022-01-13T15:38:43.663+00:00

It depends on your organization's infrastructure.
In case you are using WSUS , it could be done easily using its interface.
In other case, you might deploy PowerShell scripts.
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Rick Chaisse 6 Reputation points

2022-01-13T18:45:13.977+00:00

Problem: Microsoft had installed an update that knocked out the L2TP VPN connection.
Solution: Open an administrative command prompt.
Type: wusa /uninstall /kb:5009543 for Windows 10
Type: wusa /uninstall /kb:5009566 for Windows 11
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Eaton Blumenstein 5 Reputation points

2023-02-06T15:57:58.3766667+00:00

I do not have kb5009543 on the PC that is having the issue, is there another fix?

22H2 Windows 10
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Wasin Timsawat 0 Reputation points

2023-03-19T08:30:28.2833333+00:00

I seeking this answer for this post as well, i am stuck at this too.
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