Simple definition
Litigation Hold is an Exchange feature that preserves mailbox items even when the user modifies or deletes them.
Technical definition
The mechanism uses the mailbox recoverable-items areas to retain copies required for legal or compliance obligations for the duration of the hold.
What is it used for?
Preserve mailbox data during an investigation, litigation matter, or regulatory requirement.
Practical example
Before an employee involved in a legal matter leaves the organization, an administrator places the mailbox on hold to preserve relevant messages.
Common issues
- The hold is enabled after the required data was already removed
- Recoverable-items capacity or retention settings are not monitored
- Litigation Hold is confused with retention policies or eDiscovery
How it works / role
After the hold is enabled, the user can continue working normally, while Exchange preserves deleted items and certain modified versions in the recoverable-items area. Those retained copies remain available to compliance processes until the hold conditions end.
Related terms
eDiscovery · Exchange Online · Retention Policy Microsoft 365
Key takeaway: Exact behavior can vary by version, product, and architecture; always validate on the environment actually deployed.