Here is another error that can lead to despair, as there are several suggestions on the net for a solution, but they did not help me.
Ich habe bei einem Kunden das Exchange 2016 CU 17 installieren müssen und wie vielen bekannt ist, wird .NET Framework 4.8 dazu benötigt. Da der Kunde aber noch das CU 12 mit .NET Framework 4.7.2 installiert hatte, musste ich den Zwischenschritt über CU 14 gehen, da hier in beiden Versionen das .NET Framework 4.7.2 Supported ist. Für die CUs 15 – 18 ist das .NET Framework 4.7.2 nicht Supported.
Source: Microsoft Support Matrix
Fortunately, I download all the CUs and was able to provide the customer with CU 14. Unfortunately, Microsoft only ever offers the last two versions for download. So in my case the CU 18 and CU 17.
Yes, I know that the CUs should be installed promptly, but customers usually see things differently. It would therefore be an advantage if Microsoft could still provide the versions that are required in the support matrix.
During the installation of CU 14 I received the following error message, even after a server restart:
"Setup kann das Upgrade nicht fortsetzen, da „powershell (5140) offene Dateien aufweist. Schließen Sie den Prozess, und starten Sie Setup neu."
The value in brackets (5140) was always a different value and the process ID is displayed here. So without further ado with the Sysinternals Process Explorer looked at what was open and found the process.
Diesen kann man per Rechtsklick – Kill Process beenden und anschließend läuft das Update, ohne den Server oder die PowerShell neu zu starten.
Maybe it will help some of you and save you a little time.