Does Windows 10 VPN Bug-Fix Update cause Teams issues?

[German]A brief question: Does somebody expects issues with Microsoft Teams after installing the out-of-band updates to fix the Windows 10 VPN internet connectivity bug (like update KB4554364)? One user reported, that the receive error 4c7 during Teams re-login.


Windows 10 Update KB4554364

First a short review. In all supported versions of Windows 10 and Windows Server 2016/2019 there is a bug – caused by an update from February 2020. This bug can prevent applications from connecting to the Internet.

The network icon in the notification area of the taskbar may show limited or no Internet connection status in the Network Connectivity Status Indicator (NCSI).

Windows 10: Internet connection indicator shows issues(Source: Technet)

This can happen when a connection to a VPN is made or disconnected, or after the status between the two has changed. On affected devices, applications may also have difficulty reaching the Internet via WinHTTP or WinInet (see also my blog post Windows 10: Bug prevents (VPN) Internet access).

On March 30, 2020, Microsoft released unscheduled updates to fix this VPN bug. The update is only available for download from the Microsoft Update Catalog and must be installed manually. Here is the list of updates available for the various Windows versions:


I had reported about this in the blog post Windows 10: Updates fixes VPN bug. There I also wrote, that these updates are optional and should really only be installed by users who suffer from the bug in question.

Issues after installing Update KB4554364

German blog reader Ex0r has posted this comment in my German blog, referring to his German post at In his environment he has issues with several machines in connection with Microsoft teams after installing the update KB4554364 for Windows 10 version 1903/1909. He wrote:

some of my clients are affected by this story: KB4554364 für Windows 10

I rolled out the KB on the affected client. After that the team login went through immediately. A short time later, however, Teams dropped out again.

His clients have issues with Microsoft Teams, but I'm not sure what he means by 'dropped out again'. Addendum: Blog reader Ex0r has responded to my request and writes

a team login is not possible after closing teams. Currently I get the error code "4c7" on two systems in the home office and in the VPN.

The blog reader asks, if anyone else has issues with VPN software in connection with MS Teams and the updates. In the user's environment the Sophos (Open) VPN Client is used. The person says that they 'feel' that the update is buggy. Anyone else affected?

A possible workaround: Enable Forms Authentication

Blog reader Ex0r referred in his 2nd response to the blog post Seeing error code 4c7 in Microsoft Teams? Fix it now.The article suggests to enable Forms Authentication via the ADFS Microsoft Management Console (MMC), see also this MS support article. Blog reader Ex0r wrote:

I am working through this to rule out that it is because of this: (we also rely on ADFS).

But considering that 99% of my other home office clients don't have this problem, it's very strange.

In a follow-up mail, the reader adds: The "workaround" mentioned in the above seems to work. Currently the team login works again.

Similar articles:
Windows 10: Bug prevents (VPN) Internet access
Windows 10: Updates fixes VPN bug

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5 Responses to Does Windows 10 VPN Bug-Fix Update cause Teams issues?

  1. EP says:

    it appears that KB4554364 vpn bugfix for v1903/v1909 may cause certain WiFi connections to stop working as reported in this recent Softpedia news article:

      • guenni says:

        They are writing about that, what HTNovo reflected in a wrong way. I tried to sort it out within the blog post Windows 10: "Socket Error 0×2200021" and WiFi issues. I don't know, what's the cause – but its not KB4554364 – imho.

        Addendum: After my analysis this night, I visited this morning the Italian MS Answers forum posts again. In one (of 6) posts, a guy confessed, that it was an April fool prank, established from a group of his friends. I'm definitely pissed, that they are joking a public forum – we have enough trouble with real W10 update mess and bugs – we don't need such bullshit on top. And I'm pissed, that Microsofts Answers forum moderators had not deleted these posts. It's now the point, I'm definitively don't engage anymore in MS answers forum to support people – and also some more sites like HTNovo (beside MSPU) are now on my black list.

  2. si says:

    I tried the manual updates with a 7-day PureVPN trial and they work for me.

    • betsy says:

      yeah i did the same, didnt want to spend on a premium vpn until i was sure so the trial helped

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