KB3023607 - Microsoft Update Breaks Cisco AnyConnect VPN Client

Estimated reading time: 2 minutes

Microsoft have done it again!! They have released another Windows Update which has obviously not been fully tested and this one has caused Cisco AnyConnect VPN Client to stop working.

So if you are trying to figure out why your VPN will not connect all of a sudden – this is probably why. The update that is causing this issue is:

KB3023607

The update itself is designed to change the way TLS in Internet Explorer works, but this has also caused “Failed to initialize connection subsystem” errors when trying to start Cisco AnyConnect VPN sessions.

So, what can you do to fix it?

The simple solution is that you have to uninstall it, but you should also ensure that you have declined it in your WSUS or SCCM or other popular Windows Update system and if you are using SCCM, you could create a task sequence to remove it en masse.

If you need to know the command line for removing this update, you should try this:

 C:WindowsSystem32wusa.exe /uninstall /kb:3023607 /quiet /norestart

If you want a workaround, Cisco have given this advice which may work for you:

Exit the Cisco AnyConnect software
Ensure you close the taskbar icon in the bottom right
Right-click vpnui.exe in the Cisco AnyConnect Secure Mobility Client installation folder