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Preservation Hold Library

The Preservation Hold Library is a hidden system library that SharePoint and OneDrive create automatically when a retention policy, retention label, or eDiscovery hold applies to a site. Whenever a user edits or deletes content under retention, a copy of the original lands in this library, so compliance is preserved no matter what happens in the visible libraries. It works silently, needs no setup, and is managed entirely through Microsoft Purview.
Related Features
Adaptive Scopes, Recycle Bin, Retention Labels, Retention Policies

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

How It Works

  • Automatic creation: SharePoint creates the library the first time a retention policy, label, or hold applies to the site; there is nothing to set up
  • Copy on change: when a user edits or deletes a covered item, a copy of the original is placed in the library while the user’s change goes through normally
  • Label behavior varies: a standard retention label copies on deletion only; a record label also copies on edit, and regulatory record labels block edits and deletes entirely
  • Business as usual: users keep editing and deleting files in their libraries while the compliance copy sits safely out of sight
  • Weekly sweep: a timer job runs every seven days, and copies older than 30 days that have outlived every retention rule move to the second-stage Recycle Bin
  • Staged disposal: expired content always passes through the second-stage Recycle Bin, where site collection admins can still recover it for up to 93 days
  • Search and eDiscovery ready: retained content stays indexed, so eDiscovery and Content Search can find it even after users delete the visible copy

Limits and Nuances

  • Invisible and automatic: only site collection administrators can open it, and it cannot be created, renamed, or deleted by hand; it appears only when a retention policy or hold touches the site
  • Immutable contents: files inside cannot be edited, deleted, or moved manually, even by an admin; only retention expiry empties the library
  • Purview is the control panel: the library has no settings of its own; its behavior is driven by retention policies and labels in Microsoft Purview, whose Policy lookup shows which policy is holding content on a site
  • Storage impact: everything in the library counts against the site’s storage quota, and the Storage Metrics report shows how much space it consumes, so budget extra storage under aggressive retention
  • A third, separate safety net: it is not version history and not the Recycle Bin, but a distinct mechanism that only retention policies and holds can fill
  • Versioning nuances: new files are not copied on their first edit (turn on library versioning if every draft matters), and all versions of a retained file are stored as a single file, except records, which keep separate version copies
  • Cleanup is not instant: the timer job runs weekly and only evaluates copies older than 30 days, so expired content can sit in the library for up to 37 days
  • Retention locks actions: users cannot delete a site, library, or list under retention, and old versions accumulate and cannot be trimmed until retention ends

Common Questions About the Preservation Hold Library

What is the Preservation Hold Library in SharePoint?

It is a hidden system library that SharePoint and OneDrive create automatically when a retention policy, retention label, or eDiscovery hold applies to a site. Whenever someone edits or deletes content under retention, a copy of the original is preserved there. Users never interact with it – it exists purely so the organization can prove content was kept for compliance, audits, or litigation.

Why can’t I see the Preservation Hold Library on my site?

By design, the library is hidden from end users and even from site owners in most views. Only a site collection administrator can open it, and even then it is meant for verification rather than day-to-day use. If you do not see it at all, the site simply has no retention policy or hold applied yet – SharePoint only creates the library when one takes effect.

Does the Preservation Hold Library count against my storage quota?

Yes. Every preserved copy counts toward the site’s storage quota, and on sites with heavy editing and long retention periods the library can grow far larger than the visible content. Microsoft specifically recommends planning for additional storage when you apply retention to SharePoint, OneDrive, or Microsoft 365 Groups. The site’s Storage Metrics report shows exactly how much space it is consuming.

Can I delete files from the Preservation Hold Library?

No. Manually editing, deleting, or moving files in the Preservation Hold Library is not supported, even for administrators. Content leaves the library only when its retention period expires, at which point a weekly timer job moves it to the second-stage Recycle Bin for final deletion. If content is being held by multiple policies, the longest retention period always wins before anything is removed.

How is the Preservation Hold Library different from the Recycle Bin and version history?

They are three separate safety nets. Version history keeps prior versions of a file inside its library and is user-facing. The Recycle Bin holds deleted items for 93 days and lets users restore them. The Preservation Hold Library is compliance-driven – it keeps copies of edited or deleted content for as long as a retention policy or hold requires, regardless of what users do.

Do I need to configure the Preservation Hold Library?

No – there is nothing to configure on the library itself. Everything is controlled by retention policies and labels in Microsoft Purview, and the library appears and operates automatically. What does need planning is storage and policy scope, since broad retention can quietly consume quota. That kind of governance planning is exactly what Greg Zelfond helps organizations work through during SharePoint implementations.