Microsoft Office & CDM breaking change: We are aware that the latest version of MS Office, released 22nd September contains a breaking change to CDM which could cause work to be lost.
Source: Version 2609 , build 20430.20092 was released 22nd September 2026 via Current Channel updates and contains a version of MS Word which does not allow files to be saved correctly through Cloud Drive Mapper.
Behaviour: The following workflows are potentially impacted: • Opening a Word document from a mapped drive and using Save As • Creating a document locally and saving it to a mapped drive • Using Save a Copy to a mapped drive
Recommendation: Customers who have not yet updated Microsoft Office to Version 2609 (Build 20430.20092) should prevent or defer deployment of this Office build to devices using Cloud Drive Mapper. Customers who have already updated to the affected Office build should roll Microsoft 365 Apps back to the previous build (Version 2608 (Build 20326.20158)) and prevent Office from automatically updating to Version 2609 while the issue is being investigated.
Fix: We have raised a Bug which our development teams are working on as a priority. We will provide an update once investigations have concluded as to how we will address the issue.