Preservation Hold

A preservation hold is the hidden location where Microsoft 365 stores content that has been deleted by users (or marked for deletion) but is subject to active retention or legal hold. In Exchange, the Recoverable Items folder's Purges subfolder holds preserved items. In SharePoint and OneDrive, the Preservation Hold Library stores preserved files. Content in preservation hold is invisible to end users but discoverable in eDiscovery searches and counts against site / mailbox quota. A common operational surprise: a SharePoint site nominally below quota is actually at quota because the Preservation Hold Library has accumulated 200 GB of preserved-but-deleted content. Monitor preservation hold size in reports.