Last Logged On By in exchange manager

[aBill]

I am viewing the mail boxes in the exchange system manager. I have noticed that there are several accounts that show the "Last Logged on By" as a different user than the mailbox owner.

For example..
Mailbox A, Mailbox B, and Mailbox C all show the "Last Logged on By" as UserAccountZ.

What does this mean?

 

[wallst32]

You might see the backup service/agent account depending on what software you use. If you are seeing another username, then it's probably that user accessing a shared resource/folder (ie calender).