Microsoft Office version 2609 & CDM breaking change
Last updatepostmortemSep 28 · 07:26 UTC
MS have confirmed the breaking change and the issue of a fix over the weekend.
Microsoft admins can review the service status notification from MS here:
https://admin.cloud.microsoft/?#/servicehealth/:/alerts/OP1478558
The text from this Microsoft advisory follows:
Users may be unable to convert Microsoft Word desktop app documents to PDFs using Save As to SharePoint locations
Issue ID: OP1478558
Affected services: Microsoft 365 apps
Status: Service degradation
Issue type: Advisory
Start time: Sep 24, 2026, 7:23 PM GMT+1More info
This issue is reported to affect Microsoft Word version 2609, and some users report that version 2608 isn't affected. No error is presented and the file is instead saved to the “C:\Users\username\AppData\Local\Microsoft\Windows\INetCache\Content.MSO” folder with an incorrect file name.Additionally, this only reported to only impact converting Microsoft Word desktop app documents to PDFs using Save As and SharePoint Online as the location.
While we're focused on remediation, users that have the option to save the file locally to their computer may use this to work around the problem. Additionally, using the Export to PDF function works as expected.
Scope of impact
This event may impact any user on version 2609 attempting to save Microsoft Word desktop app documents as PDFs to SharePoint Online. This information may be updated as our investigation continues.Root cause
A recent Microsoft Word change relating to the Save As filename validation path to cloud-backed locations, which prevents the SharePoint save flow from completing and is causing impact.Current status
Sep 25, 2026, 8:28 PM GMT+1
We've confirmed that the issue is related to a recent Microsoft Word change affecting Save As filename validation for cloud-backed locations. This validation issue prevents the SharePoint save process from completing successfully during PDF conversion. We're actively deploying a change to disable the impacting behavior and expect this deployment to be completed by our next scheduled update.
Next update by:
Monday, September 28, 2026 at 10:00 PM GMT+1
Reported by IAM Cloud on their status page.