Late breaking news for May’s Windows 11 22H2 cumulative update

LCU KB5026372 for Windows 11 22H2 is breaking L2TP/IPsec VPN connections.

Last weekend we started seeing reports of VPN problems after installing KB5026372 (Preview KB5025305 also affected).  Apparently the VPN will connect but the speeds are extremely slow and RDP becomes unusable. Some have reported the problem is limited to Wi-Fi connections but we have not seen that confirmed by multiple sources.  Some other less common problems have also been reported – see links  below.

It has been stated Microsoft is aware of the issue and is investigating but they have not yet acknowledged this as a “Known Issue” on KB5026372 KB page.

Until Microsoft releases an update, the “fix” is to uninstall KB5026372. Be aware this is a cumulative patch and removing it will also remove all other protections in May’s release.  Also because this LCU includes a new SSU you will need to use the DISM/Remove-Package command line option instead of running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch. See “If you want to remove the LCU” below.

Microsoft investigates slow Windows VPN speeds after May updates

https://www.bleepingcomputer.com/news/microsoft/microsoft-investigates-slow-windows-vpn-speeds-after-may-updates/

Microsoft confirms issues in Windows 11 KB5026372 May 2023 update

https://www.windowslatest.com/2023/05/17/microsoft-investigates-issues-in-windows-11-kb5026372-may-2023-update/

You might have VPN issues after installing Windows 11 KB5026372

https://windowsreport.com/kb5026372/

Microsoft Acknowledges Slow VPN Connection Issues on Windows 11

https://petri.com/microsoft-slow-vpn-connection-windows-11/

May 9, 2023—KB5026372 (OS Build 22621.1702)

https://support.microsoft.com/en-gb/topic/may-9-2023-kb5026372-os-build-22621-1702-ce93c18e-e819-458f-abcf-dc7154ce7e40

If you want to remove the LCU

To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.

Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.