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Steps:

  1. On the affected server go to C:\Windows\System32\inetsrv\Config
  2. Open applicationHost.config
  3. Search for .msu
  4. Find this:

        <system.webServer>

            <webSocket enabled="false" receiveBufferLimit="4194304" pingInterval="00:00:10" />

            <staticContent>

                <mimeMap fileExtension=".msp" mimeType="application/octet-stream" />

                <mimeMap fileExtension=".msu" mimeType="application/octet-stream" />

                <mimeMap fileExtension=".apk" mimeType="application/octet-stream" />

            </staticContent>

        </system.webServer>

  1. Remove <mimeMap fileExtension=".msu" mimeType="application/octet-stream" />
  2. Save file
  3. Problem resolved

 

FYI, this was also for Windows 2019   KB5022840.

These Windows updates first appeared 14 Feb 2023.


Oh wow thanks Phil.


Can this be done proactively before the MS patch is installed? Or should the patches be blocked from installing on servers? My UAT servers was impacted, but my production servers are schedule and not patched yet


Hi Kyle,

I was told it can only be resolved after the KB was deployed and not ‘fixed’ proactively as it is something added by the KB.

Even rolling back the KB does not change the configuration file to the original settings.

It is a line added by the KB according to my source and it basically is a duplicate of another line in the configuration file which is located in another section.

Further, this should only be removed if your server is impacted negatively by this KB.  Not all servers have the issue as they may not have had the original .msu line in it already.

Hope this clarifies.

 

 

 


The key is avoiding the issue entirley. Either block the patch install, or modify the config file prior to deployment. I need to avoid potential  production server outage.

The KB article KB5022840 adds .msu to MIME Type. Your suggested fix avoids the issue by removing from config file. Should be safe to modify config file prior to patch.

 


Hello Kyle.

I think, if I remember correctly, the patch will overwrite that config file and you need to make manual changes again.


Thanks, We are going to block the patch from our prod servers, and backup the config file. Unfortunately there is no way to know if Microsoft will do something similar on future patches


They will, I’m sure of it.


Hi @Luis Aguero similar issue happened in our production environment with KB5028623 and I had to remediate the config file by removing the duplicate entry.

Have you observed such issue with this KB article in any other environment? Our team needs few instances to take it to the Microsoft.


Thanks for adding KB5028623 to the conversation Deepesh.  Yes, per our meeting this is a legitimate patch that will cause the issue for those customers still on versions that are pre-HF27.


FYI, this was also for Windows 2019   KB5022840.

These Windows updates first appeared 14 Feb 2023.

This also seems to occur with KB5029647


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