Some users may be missing options to open files using custom file handlers in SharePoint Online 

Title: Some users may be missing options to open files using custom file handlers in SharePoint Online  User impact: Some users may be missing options to open files using custom file handlers in SharePoint Online  More info: Custom file handlers enable users to open files with integrated third-party or line-of-business apps. For example, some users may have been missing the “Open in Adobe Acrobat” option for PDF files. Final status: We've completed our rollback of the identified updates responsible for this impact and have confirmed through service-side testing as well as testing with previously affected users that this is mitigated. Due to cache storage, this can take up to 48 hours to resolve for all users. If users are in need of immediate remediation, please follow the articles below: https://learn.microsoft.com/en-us/onedrive/developer/file-handlers/?view=odsp-graph-online&source=recommendations https://learn.microsoft.com/en-us/onedrive/developer/file-handlers/reset-cache?view=odsp-graph-online Scope of impact: Some users attempting to open files using custom file handlers in SharePoint Online may have been impacted.  Start time: Sunday, March 29, 2026, at 11:00 PM UTC End time: Wednesday, April 15, 2026, at 2:06 PM UTC Root cause: A recent service update to SharePoint Online that changed how custom file handlers are resolved resulted in impact. Next steps:  - We'll continue our review of the impacting update to better understand how the change resulted in impact and what we can do to improve our pre-deployment processes to identify and resolve similar issues. This is the final update for the event.

Title: Some users may be missing options to open files using custom file handlers in SharePoint Online and Microsoft OneDrive User impact: Users may be missing options to open files using custom file handlers in SharePoint Online and OneDrive. More info: Custom file handlers enable users to open files with integrated third-party or line-of-business apps. For example, some users may be missing the “Open in Adobe Acrobat” option for PDF files. Current status: We’ve determined that a recent service update to SharePoint Online and OneDrive may be contributing to impact. We’re reverting the aforementioned update to see whether it mitigates the impact while we continue to validate the root cause. Scope of impact: Some users attempting to open files using custom file handlers in SharePoint Online and OneDrive may be impacted. This information may be updated as our investigation continues. Next update by: Wednesday, April 15, 2026, at 4:30 PM UTC

Title: Some users are missing the “Open in Adobe Acrobat” option for PDF files in Microsoft OneDrive and SharePoint Online User impact: Users are missing the “Open in Adobe Acrobat” option for PDF files in OneDrive and SharePoint Online. Current status: We’ve determined that a recent service update to SharePoint Online and OneDrive may be contributing to impact. We’re reverting the aforementioned update to see whether it mitigates the impact while we continue to validate the root cause. Scope of impact: Your organization is affected by this event, and some users attempting to access PDF files in OneDrive and SharePoint Online may be impacted. This information may be updated as our investigation continues. Next update by: Wednesday, April 15, 2026, at 3:30 PM UTC

Title: Some users are missing the “Open in Adobe Acrobat” option for PDF files in Microsoft OneDrive and SharePoint Online User impact: Users are missing the “Open in Adobe Acrobat” option for PDF files in OneDrive and SharePoint Online. Current status: We’re reviewing HTTP Archive (HAR) files and Console logs to understand why the option is missing for some users and determine the appropriate mitigation. We’re reaching out to your organization’s representatives to collect additional HAR files for our investigation. Scope of impact: Your organization is affected by this event, and some users attempting to access PDF files in OneDrive and SharePoint Online may be impacted. This information may be updated as our investigation continues. Next update by: Wednesday, April 15, 2026, at 1:30 PM UTC

Title: Some users are missing the “Open in Adobe Acrobat” option for PDF files in Microsoft OneDrive and SharePoint Online User impact: Users are missing the “Open in Adobe Acrobat” option for PDF files in OneDrive and SharePoint Online. Current status: We’re reviewing configuration and service-side factors to determine why the option is available for some users but missing for others. Scope of impact: Your organization is affected by this event, and some users attempting to access PDF files in OneDrive and SharePoint Online may be impacted. This information may be updated as our investigation continues. Next update by: Wednesday, April 15, 2026, at 12:30 PM UTC