You are trying to update your server with some bigger update – lets say SQL SP or an update for the System Center and in the process of updating you get error 20000009.
Recently we had “Patch Monday” – unusual since we usually patch on Fridays (in case something goes wrong we have weekend ahead), but this one time was good opportunity since there was some infrastructure work and we had planed downtime and we took the opportunity to patch.
Unfortunately something went very wrong. First after rebooting one of the Exchange servers I got following error:
Exchange ECP / The LDAP Server is unavailable
“Topology Provider couldn’t find the Microsoft Exchange Active Directory”
I thought that errors while updating Hyper-V Integration Services were thing of a past, but Microsoft Updates from January and February 2018 are proving me wrong https://www.informaticar.net/windows-server-2012-r2-with-exchange-failing-kb4072650-and-kb-4057903/. The problem is, you update Hyper-V Integration Services on Windows Server 2012 R2 with Exchange install on it and it freezes.
In my experience it does not happen on every installation, one member of an Exchange DAG would pass update normally, while other one would fail, and both have exact same configuration, so the problem is quite unusual. Read More
Something scary happened recently, some of the Windows Server 2012 R2 installations totally froze on startup after Windows update with “Getting Windows Ready” message spinning for 20-30 minutes. Eventually just blank desktop appeared with only start button and unresponsive taskbar. Read More
These commands are mostly useful while upgrading CUs on Exchange 2013/2016 and if there is some kind of maintenance that requires stopping Exchange services.