The Windows updates that Microsoft released on 11.01.2022 are causing some problems on Windows servers. In the meantime, there are increasing reports that domain controllers keep restarting after January CU has been installed. Some other problems seem to increasingly affect Windows Server 2012 R2. After installing the update, Hyper-V no longer starts and partitions formatted with ReFS are no longer readable.
As if that wasn't enough trouble, there are also problems with L2TPoverIPSEC in Windows 10 and Windows 11, which also affects VPN connections from other manufacturers such as Cisco, Sonicwall and Fortinet.
The problems with Hyper-V and the domain controllers alone have the potential to paralyze a company, and broken VPN connections do the rest.
Although the updates are intended to fix some critical security vulnerabilities in Windows, the updates cannot currently be installed on domain controllers due to the problems. The following KBs currently cause the boot loop on domain controllers:
- KB5009586 (Windows Server 2022)
- KB5009557 (Windows Server 2019)
- KB5009546 (Windows Server 2016)
- KB5009624, KB5009595 (Windows Server 2012 R2)
To be on the safe side, these updates should be uninstalled from domain controllers. Unfortunately, removing the updates also takes quite some time, there are reports that the restart after removing the Updates up to 30 minutes can take.
The updates can be uninstalled with the following command:
wusa /uninstall /kb:5009586
If the server restarts too quickly, safe mode or disconnecting the network connection will help.
The updates are still being offered for installation and have not yet been withdrawn:
For domain controllers, Hyper-V servers or servers that use ReFS partitions, it is currently better not to install the updates and to block or reject them on the WSUS. The Exchange updates which also published yesterday are not affected by this problem.
Update 19.01.22: Mittlerweile hat Microsoft neue Updates veröffentlicht, welche die Probleme beheben sollen. Mit den neuen Updates sind aktuell keine Probleme bekannt. Bereits aktualisierte Systeme sollten jetzt also auch die neuen Updates erhalten. Systeme die bisher nicht mit den „alten“ Updates aktualisiert wurden, können nun mit den neuen Updates versorgt werden. Sie Updates beheben teils kritische Sicherheitslücken und sollten daher zeitnah installiert werden.