An error occurred during the installation of assembly: Exchange Update and Windows January Update problems

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Here in the forum and on the Exchange Team Blog there are indications that the installation of the November update for Exchange Server 2016 / 2019 may cause problems. It seems that once again there are problems with servers with German or non-English operating systems when the January update for the Windows Server is installed. The error and its possible solution also seem quite familiar to me. If I'm not mistaken, the problem has existed before.

When trying to install the November Update for Exchange Server on a Windows Server with the January Update installed, the following error message appears:

Exchange November Update and Windows January Update problems
An error occurred during the installation of assembly 'Microsoft.Exchange.Data.Common,version="15.1. 2503.00", fileVersion="15.1.2507.44", culture="neutral",publicKeyToken="31BF3856AD36435", processor Architecture ="MSIL". For more information, refer to Microsoft Help and Support. HRESULT: 0x80070087.

At the time of the installation attempt, all Exchange services were still started. After restarting the server, the Exchange services were no longer started despite the "Automatic" start type. The Exchange server was therefore no longer functional after the restart.

Daniel has the solution to this error in the Forum posted. Thank you very much for the detailed article. Let me summarize briefly:

In the Exchange installation directory there are errors in the file "V15\bin\servicecontrol.ps1", apparently the commands "Stop-SetupService" and "Start-SetupService" are used here, but they do not exist.

Daniel has worked around this problem by adapting the script and adding appropriate aliases. He has written his solution in great detail in the forum so that the corresponding changes can be reproduced.

I don't remember the commands "Stop-SetupService" and "Start-SetupService", I think that was a problem before. Probably an old error has crept in again.

Incidentally, I was also unable to reproduce the problem on Exchange servers with an English operating system and January update. Unfortunately, there are always problems on operating systems in other languages.

If the Exchange November Update still needs to be installed, it is probably better to install the Exchange Update first and then the January Windows Update. I don't think Microsoft will release a new security update for Exchange now or fix this problem.

The CU15 for Exchange 2019 should not be long in coming, as CU15 contains the November update, the update should be tested thoroughly.

6 thoughts on “An error occurred during the installation of assembly: Exchange Update und Windows Januar Update Probleme”

  1. Laut Microsoft lediglich ein Reboot-Problem, wie nun im offiziellen Exchange Blog zum November Update hinzugefügt wurde:

    Based on our current understanding of this problem, this issue can occur if the January 2025 .NET Cumulative Update was installed but the server was not rebooted after the installation, or the .NET Cumulative Update and Exchange Server November Security Update were installed at the same time (same maintenance window, without a reboot between the two).

    If the .NET update is installed but the server is not rebooted, certain files are kept in locked state and Exchange SU update fails accessing them during Setup, leading to the error mentioned.

    Reply

    • Wäre wünschenswert, aber wer installiert das .Net Januar 2025, um dann wie im Bild oben, aus dem Downloads Ordner das Exchange Sicherheitsupdate zu starten. .Net hängt doch so stark mit Exchange zusammen, ich würde nie auf die Idee kommen, bei einem ausstehenden .Net Update (Neustart) ein SU zu installieren. Und die Leute die es stets nachgestellt haben, haben wenn doch nur das SU installiert und nicht immer wieder das .Net vorher. Nur mal meine Gedanken dazu, die ich auch schon im MS Blog dazu hatte.

      Reply

      • Ich habe es gerade auf einem Exchange 2016 ausprobiert auf dem die Installation vorher abgebrochen war. Nach einem sauberen Neustart lief die Installation nun erfolgreich durch.
        Nach der Installation der Windows und .Net Updates wurde eigentlich ein Update durchgeführt.

        Reply

  2. Ja, kann ich auch so bestätigen, denn das Novemberupdate schon drauf war, macht das Januar SU keine Probleme. Wir haben unseren Exchange auf deutsch.

    Reply

  3. Hallo zusammen!

    Wie verhält es sich denn, wenn das Nov24SUv2-Update bereits installiert war und jetzt die Jan25-Updates für den Server installiert werden? Ich verstehe Den Text oben so, dass es in dieser Konstellation keine Probleme gibt (bzw. zumindest bis jetzt keine bekannt sind), ist das zutreffend?

    DANKE!

    Reply

    • Also zumindest bei uns war diese Reihenfolge kein Problem. Das Exchange November v2 Update war bereits installiert und unser Exchange 2019 hat ohne zu murren das Windows Update vom Januar installiert und es läuft auch immer noch alles.

      Reply

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