It looks like Microsoft has decided to make an original New Year's.jpgt and extend the New Year's holidays a little more, releasing an update that makes it impossible to connect to VPN using the L2TP protocol, which is often used for remote work. The fact that Windows updates bring not only fixes but also new bugs is no longer news. However, in view of the fact that this problem is widespread due to the high probability of the appearance and the large spread of remote work, I decided that it would be nice to warn the community.

So, the updates from January 11, 2022, which are probably the cause of this problem:

Windows 10 - KB5009543 (KB5008876 also mentioned)

Windows 11 - KB5009566 (KB5008880 also mentioned)

If the update has already been installed, as a solution to the problem, at the moment, only a rollback of the update is offered, for example, with the following PowerShell script (administrator rights are required).

if (get-hotfix -id KB5009543) {wusa / uninstall / kb: 5009543}

If there are other solutions, I will add them at the end of the publication.

If the update has not yet been installed, it is recommended to use the update pause function.

Discussion of the problem on Reddit (and hate in favor of Microsoft)

From myself I wish you more benefits and fewer bugs in the New Year!

bbabo.Net