The Preservation Hold Library is a hidden system library in SharePoint and OneDrive that automatically preserves copies of content affected by retention policies or legal holds, ensuring compliance even when users edit or delete content.

Common Use Cases

• Microsoft 365 retention policies: retain content for a defined period regardless of user actions
• Legal holds and eDiscovery: preserve content for investigations, audits, or litigation
• Protection against user deletion: ensure content is retained even after deletion from libraries
• Tracking content changes: preserve original versions when files or pages are modified
• Regulatory compliance: meet legal, financial, or industry-specific record-keeping requirements

Benefits

• Automatic and invisible: operates silently in the background without user interaction
• Deletion-proof retention: content cannot be permanently deleted while under retention
• Preserves original versions: when content is edited, prior versions are copied to the library
• Supports compliance workflows: retained content remains searchable for eDiscovery
• Policy-driven behavior: fully controlled by Microsoft 365 retention and hold policies
• Applies to pages and files: preserves documents and even SharePoint pages

Key Considerations

• Hidden system library: not visible to end users and not meant to be accessed directly
• Created automatically: the library is created when a retention policy or hold applies to the site
• Storage impact: preserved copies count toward site storage and can significantly increase usage
• Not version history: this library is separate from version history and the Recycle Bin
• Content is immutable: files in the Preservation Hold Library cannot be edited or deleted manually
• Retention controls cleanup: content is removed only after the retention period expires