Why do you need to know about non-owner mailbox access?

• To identify unauthorized access to mailbox data by users within and outside your organization.
  
• To provide relevant information such as the state of mailbox data at a given time, who sent e-mail from a mailbox, and if a particular person viewed mailbox data, to legal cases and during auditing.
  
• To enforce compliance and privacy regulations.
  

How does O365 Manager Plus help?

O365 Manager Plus' Non-owner Mailbox Access Report lists all mailboxes access by non-owners. This prepackaged report lists important details such as:

• Who accessed which mailbox and when. 
  
• Actions performed by the non-owner. 
  
• Whether the action was successful.
  
• Type of client used.
  
• Client IP address, and more.
  

Using the built-in filter, you can choose to exclude the mailboxes accessed by administrators and delegated users as they also fall under the non-owner category.

Steps to generate non-owner mailbox access report

1. Go to the Reports tab.
   
2. Select Security Reports under Other Services from the left pane.
   
3. Choose Non-owner Mailbox Access under the User Activities Reports category.
   

You can refine the result to find out specific details such as the non-owner access on a specific mailbox, from a specific client IP, in a specific time period, and more, using the built-in filter.