Mailbox audit logs are generated for each mailbox that has mailbox audit logging enabled. Log entries are stored in the Audits subfolder of the audited mailbox Recoverable Items folder. This ensures that all audit logs are available from a single location, regardless of which client access method was used to access the mailbox or which server or workstation an administrator used to access the mailbox audit log. If you move a mailbox to another Mailbox server, the mailbox audit logs for that mailbox are also moved because they're located in the mailbox.

By default, mailbox audit log entries are retained in the mailbox for 90 days. You can modify this retention period by using the AuditLogAgeLimit parameter with the Set-Mailbox cmdlet. If a mailbox is on In-Place Hold or litigation hold, audit logs are retained until the hold is removed.

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Mailbox audit logging is enabled per mailbox. Use the Set-Mailbox cmdlet to enable or disable mailbox audit logging. For details, see Enable or Disable Mailbox Audit Logging for a Mailbox.

When you enable mailbox audit logging for a mailbox, access to the mailbox and certain administrator and delegate actions are logged by default. To log actions taken by the mailbox owner, you must specify which owner actions should be audited. The following table lists the actions logged by mailbox audit logging, including the logon types for which the action is logged.

Mailbox actions logged by mailbox audit logging

Action	Description	Administrator	Delegate	Owner
Copy	An item is copied to another folder.	Yes	Yes	Not applicable
Create	An item is created in the mailbox. (For example, a message is sent or received.) Note: Folder creation isn't audited.	Yes*	Yes*	Yes
FolderBind	A mailbox folder is accessed.	Yes*	Yes**	Yes
HardDelete	An item is deleted permanently from the Recoverable Items folder.	Yes*	Yes*	Yes
MessageBind	An item is accessed in the reading pane or opened.	Yes	Not applicable	Not applicable
Move	An item is moved to another folder.	Yes*	Yes	Yes
MoveToDeletedItems	An item is moved to the Deleted Items folder.	Yes*	Yes	Yes
SendAs	A message is sent using Send As permissions.	Yes*	Yes*	Not applicable
SendOnBehalf	A message is sent using Send on Behalf permissions.	Yes*	Yes	Not applicable
SoftDelete	An item is deleted from the Deleted Items folder.	Yes*	Yes*	Yes
Update	An item's properties are updated.	Yes*	Yes*	Yes

* Audited by default if auditing is enabled for a mailbox.

** Entries for folder bind actions performed by delegates are consolidated. One log entry is generated for individual folder access within a time span of three hours.

Mailbox access by authorized automated processes such as accounts used by third-party tools or accounts used for lawful monitoring can create a large number of mailbox audit log entries and may not be of interest to your organization. You can configure such accounts to bypass mailbox audit logging. For details, see Bypass a User Account From Mailbox Audit Logging.

If you no longer require certain types of mailbox actions to be audited, you should modify the mailbox's audit logging configuration to disable those actions. Existing log entries aren't purged until the configured audit log age for the mailbox is reached.

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You can use the following methods to search mailbox audit log entries:

• Synchronously search a single mailbox   You can use the Search-MailboxAuditLog cmdlet to synchronously search mailbox audit log entries for a single mailbox. The cmdlet displays search results in the Exchange Management Shell window. For details, see Search the Mailbox Audit Log for a Mailbox.
  
  
• Asynchronously search one or more mailboxes   You can create a mailbox audit log search to asynchronously search mailbox audit logs for one or more mailboxes, and then have the search results sent to a specified email address. The search results are sent as an XML attachment. To create the search, use the New-MailboxAuditLogSearch cmdlet. For details, see Create a Mailbox Audit Log Search.
  
  
• Use auditing reports in Exchange Administration Center (EAC)   You can use the Auditing tab in (EAC) to run auditing reports or export entries from the mailbox audit log and the administrator audit log. For details, see Auditing Tab.
  
  

The following table describes the fields logged in a mailbox audit logging entry.

Mailbox audit log fields

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