Outlook moves all messages from Exchange server

My boss is having a problem with Outlook 2011 on her MacBook Pro. We have an Exchange 2010 server and whenever she receives new mail while Outlook is open, it saves it to her computer instead of the server. Emails may pop up briefly on her iPhone and iPad however as soon as Outlook sees the emails, it snatches them away from the devices.

The account is set up as an Exchange account on her computer, not POP3. There are no rules on the computer or the Exchange account.

I tried deleting the account from her Mac and adding it back again but it started removing ALL emails from her Exchange account and moving them into her "On My Computer" inbox. She has dozens of folders to manage her emails and I would watch as the folders would be emptied and the emails were placed in her computer inbox. To keep from having all of her emails dumped into one bin on her computer, I moved Outlook to offline mode and am having her use the Mail app in the interim.

I have looked everywhere on the computer for a hidden setting that would tell Outlook to move everything but cannot find it. Can anyone offer any suggestions??

In Outlook go to Tools> Accounts. Click on her account (probably only one in there), and in the lower right click Advanced. You'll advance to a window showing the Server options- click "Leave a copy of each message on server". You can also choose to delete messages after certain times (probably want never here).

Hope that helps.