Legal Holds are a feature available as a part of Box's Governance package. You can use legal holds to place a hold on users and content related to a litigation or investigation. This hold will prevent any content pertinent to the legal matter from being permanently deleted.
Legal Holds allow you to place holds on four kinds of objects:
A managed user in your enterprise
The policy will hold everything that user has access to (owned or collaborated) or has interacted with in the selected date range.
Folder (API only)
File (API only)
Specific file version (API only)
Custodian actions that trigger Legal Hold
Download (Including files downloaded via Box Sync and Box Edit)
Upload (Including files uploaded via Box Sync and Box Edit)
File is Edited
Box Note is Opened
Item is sent to trash (If folder is trashed, all items within folder are held)