Update error code 30088-27 Office 2021 what to do to get corrected????

Hi everyone!

Briefly for info for those who are not already aware.

Last night (my time zone), Microsoft 365 got an update to version 2408 16.0.17928.20114. I updated Microsoft 365 with its internal update function. After that, I tried out if the error message pops up again and see, everything works fine and no error message is shown again. :-)

BTW... I have enabled all privacy settings (no optional data is transfered to Microsoft).

Greets from Switzerland

Uwe

I tested using two methodologies.

I took a device inside my network behind Firewalls and Proxies and it failed.

I took the same device and plug edit into a home network without firewalls and Proxies and it worked.

We then used Fiddler and Wireshark to analyze the traffic and found that connections to Microsofts CDN when we invoked the Clicktorun were not using the WinInet Proxy.

Our Proxies were configured for Authentication for Microsofts CDNs. When we disabled Authentication, as is required for WinHTTP Proxy, the Click to run worked and our Office started to update. We've had 4000 Systems stuck on June's update for 2 months, As of today we've been able to patch 3000 systems with this firewall/proxy change.

I have identified a solution that address this specific issue, as this exact problem affected my environment starting with the June Office Updates.

It appears that Microsoft has changed the communication method for Office Click-to-Run. Previously, OfficeC2Rclient.exe used the WinInet proxy settings (Internet Settings) to connect to Microsoft's cloud services. However, following the June update, OfficeC2Rclient.exe now utilizes the WinHTTP proxy (configured via NetSH) for communication.

Depending on your environment's configuration, systems without a properly configured WinHTTP proxy will default to using the Default Gateway to access the internet. This could result in traffic being blocked by your Default Gateway Firewall, as such traffic typically routes through a proxy. In environments where a WinHTTP proxy is configured to use an actual proxy server, authenticated proxy rules may cause the traffic to fail with a 407 error, as the Windows WinHTTP proxy does not handle authentication well.

In our environment, we addressed this by reconfiguring our firewalls and proxies to allow the necessary communication. Given the risks associated with recent CVEs affecting Office products in the past couple months, I hope this information helps others who have been unable to update their Office installations, thereby reducing their exposure to potential vulnerabilities.

I performed the command line update and my Office 2021 updated to the latest version (2408). However, my manual updating is still broken, showing the Error Code.

Briefly for information.

Version 2408 16.0.17928.20066 is available on the release channel and the manuel update worked well so far now (at least for me). Release notes are following...

You can also update Office by using the following well known command line:

"C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.17928.20066

Still working fine here after the update from within Office.