We’re deprecating the previewImageUrl property in the resourceVisualization complex type for Insights items where the referenced resource is a file attachment (resourceReference.type = fileAttachment). This affects responses from the Insights List shared and Insights List used APIs when the underlying resource is an email attachment.

What’s changing and why

The previewImageUrl property is no longer returned for file attachment items. File attachments don’t have a consistent preview experience across Microsoft 365, so removing this property simplifies the API and aligns it with supported preview scenarios. Items that reference cloud files (like driveItem) aren’t impacted.

Timeline

• Deprecation notice: Effective immediately
• Removal date: November 1, 2027

Action required

• If your app uses resourceVisualization.previewImageUrl for file attachment insights, update your logic to handle the absence of this property.
• For previews, prefer modern attachments (cloud files) and use the driveItem: preview action where applicable.

Resources

• List shared
• List used
• officeGraphInsights resource type
• sharedInsight resource type
• resourceVisualization resource type
• driveItem: preview