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PaulH1980's avatar
PaulH1980
Copper Contributor
Sep 10, 2025

Hotfix update for 2016 CU23 HU18: (KB5066370) breaks OWA and leaves all services disabled

Has anyone else applied the latest hotfix?  First of all it tries to validate open files instead of just killing these processes as part of the update, then after rebooting all the services are left in a disabled state.  Then I discover it has broken IIS and OWA doesnt work.

 

We have had client issues all day in the office.  It looks like another update has been pushed out without sufficient testing.

 

Any help would be grateful at this point, I am looking to take 2 out of 4 servers offline.

2016
Exchange Server

1 Reply

  • itechniker's avatar
    itechniker
    Occasional Reader
    Sep 18, 2025

    Had the same problem on one server (german language, Windows Server 2016).

    I wanted to fix it by an CU23 inplace upgrade, but during the first step (language files) the setup ended with this message:

    Das Produkt mit dem Code 9bbcb564-aac3-4bf5-042c-a4d51a19bf14 kann nicht entfernt werden. Installation angehalten,
unvollständig. Fehlercode: 1604. Letzter vom MSI-Paket ausgegebener Fehler: 'An installation for Microsoft Exchange
Server is currently suspended. You must undo the changes made by that installation to continue. Do you want to undo
those changes?'. Der Befehl 'Uninstall-MsiPackage -LogFile
'C:\ExchangeSetupLogs\Uninstall.az-latn-az.owaplus.20250918-171656.msilog' -ProductCode
'9bbcb564-aac3-4bf5-042c-a4d51a19bf14'' wurde ausgeführt.

     

    So then I executed this powershell command:

    Uninstall-MsiPackage -LogFile 'C:\ExchangeSetupLogs\Uninstall.az-latn-az.owaplus.20250918-171656.msilog' -ProductCode '9bbcb564-aac3-4bf5-042c-a4d51a19bf14'

     

    After that the OWA was healthy again.

    As I check the Windows Updates I saw that KB5066370 was installing again - I waited until it finished (took some time) and then restarted the server after the update (as the server was requesting it for the update).

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