Litigation Hold vs. Single Item Recovery vs. Retention Hold

Many administrators confuse Litigation Hold with Single Item Recovery and Retention Hold. However, they provide different functionalities and, therefore, are appropriate for some situations and not for other. Here is a simple overview of all three:

Litigation Hold, as explained before, is used during a lawsuit, investigation or similar events to preserve mailbox items from inadvertent or purposeful modification or deletion by the user (or someone with access to the mailbox) and from automated deletion by retention policies. Until the hold is removed, deleted items are not purged from the mailbox database and if a mailbox item is modified, a copy of the original item is also retained. These are returned in Discovery searches performed when the mailbox is on Litigation Hold. Any retention policies applicable to the mailbox don’t need to be suspended. Because messages continue to be deleted as expected (except from the Recoverable Items\Purges folder!), users may not notice they’re on Litigation Hold.

Single Item Recovery preserves items that users purged from their Recoverable Items\Deletions as well as modified items until the deleted item retention period is reached (14 days be default). To the user the items will look purged, but they can still be recovered by an administrator.

Retention Hold prevents retention policies from deleting or moving e-mails to the user’s personal archive for a period of time while the user is temporarily away from work (holidays, sabbatical leave, etc.). Note that this does not affect the mailbox quota – if a user has ProhibitSendReceiveQuota set, e-mails will get bounced back if the mailbox goes over quota! Deleted messages are not treated any differently when a mailbox is on Retention Hold.

The following table hopefully will make the differences even clearer: