KB5028166 is causing system issues, break Secure Channel, forces Synology to release a patch

Last week, Microsoft released the KB5028166 update for Windows 10 users as a part of its monthly Patch Tuesday updates. However, it looks like the latest update did more harm than good as users are now reporting various issues after installing the new update.

According to reports on Reddit, Windows 10 users have reportedly noticed a system slowdown after installing the latest update. The issue extends to apps in general, including Microsoft's own apps as well as games with users reporting a drop in frame rates.

Unfortunately, that's not all as reports also suggest KB5028166 causing network issues for Windows 10 users. These issues include problems connecting to the internet and missing Bluetooth drivers after installing the latest update.

If that was not all, Microsoft's latest update seems to have hit enterprise customers as well. As pointed out by u/luckman212 on Synology's subreddit, users are facing issues establishing a secure channel after upgrading their system, causing them to lose connection with their Network Attached Storage (NAS).

Long story short, Microsoft released some updates for Win10/11 this month that destroyed the ability for our fully patched Win10 22H2 clients to establish a secure channel with the domain controller running on our Synology. The reason I even discovered this was users complaining about not being able to connect via Remote Desktop (RDP) anymore (NLA errors).

The usual fixes (unjoin/rejoin, or running Test-ComputerSecureChannel -Repair -Verbose failed. As did all sorts of monkeying around with the Registry, DNS settings, updating NIC drivers, manual editing of smb.conf and mustache files, staring at Wireshark packet dumps, etc...

Unfortunately, the issue forced Synology to release an emergency patch to fix the issue. According to the company, the issues impacts users who have Synology Directory Server package installed and have domains created by Synology Directory Server. If a user meets these conditions and installs the Windows 10 KB5028166 update, they will not be able to establish a Remote Desktop session or open specific RSAT management tools. Synology has released a patch to address the issue and the company is recommending users to manually download and install the patch from the Package Center.

Microsoft is yet to acknowledge any of the issues that have been raised by users, so we don't know the exact reason or the extent of the impact.

We here at Neowin recommend enabling System Restore on the Windows install disk (usually C:\) and doing a System Restore Point before installing Patch Tuesday updates, but also before installing 3rd party software on your system.