🔐 🔐 Microsoft Purview is finally bringing sensitivity labels to SharePoint data at rest

I’m excited to see Microsoft Purview Information Protection introducing the ability to automatically apply a SharePoint document library’s default sensitivity label to existing files (data at rest).

Today, default sensitivity labels help ensure that new and modified documents are classified correctly. However, many organisations still have thousands of legacy documents that remain unlabelled or inconsistently classified.

With Microsoft 365 Roadmap ID 559105, Microsoft is closing that gap.

What this means

When enabled, SharePoint will be able to evaluate documents already stored within a library and automatically apply the library’s configured default sensitivity label to files that aren’t already appropriately classified.

This brings the same protection model used for new content to historical content as well.

Why it matters

✅ Improved compliance – Legacy documents can be brought into alignment with organisational data protection policies.

✅ Consistent classification – Reduces situations where files within the same library have different or missing labels.

✅ Reduced administrative overhead – No more large-scale manual relabelling exercises for existing content.

✅ Stronger Zero Trust posture – Helps ensure that sensitive information is consistently identified, classified and protected.

✅ Better governance – Supports requirements where all content within a repository must carry the correct protection label.

Real-world examples

📁 HR libraries where historical employee records automatically receive a Confidential – HR label.

📊 Finance repositories where years of financial reports inherit the correct confidentiality classification.

⚖️ Legal document stores where legacy contracts become consistently protected without manual intervention.

🚚 Migration projects where content moved from file shares or third-party platforms can automatically receive the appropriate sensitivity label after migration.

For organisations investing in Microsoft Purview, this feels like a significant step forward. Sensitivity labels become far more valuable when they can help protect not only future content, but also the vast amount of information that’s already stored across SharePoint.

Sometimes the most impactful security improvements are the ones that quietly solve longstanding operational challenges.