Microsoft developers are investigating an issue with slow connection speeds when using L2TP and IPsec VPN connections on Windows 11 devices. Significant slowdowns in VPN connection speeds are observed after installing the May Cumulative Operating System Update.
According to reports, the mentioned problem was already known in April when Microsoft released the optional update KB5025305 for Windows 11. This package later became part of the mandatory update KB5026372, which began rolling out in May. According to the source, both service packs cause an issue with L2TP and IPsec VPN connections.
It is noted that there are no problems with the connection itself, but after installation the connection speed remains minimal. In addition, installing one of the updates mentioned leads to frequent RDP connection failures. The issue appears to occur when using a wireless connection over Wi-Fi, but does not affect devices using a wired Internet connection.
A Microsoft spokesman confirmed that the company is aware of the issue and is currently working on a fix. Until the relevant patch is released, the only way to restore normal VPN connection speed is to remove problematic updates from the device. However, this will also remove other patches it contained, including security fixes. When Microsoft might release a fix to fix the VPN connection issue in Windows 11 is still unknown.