Environment:
We have 2 users that do not get new mails automatically with Outlook 2011 for Mac. They have the latest version of Office 2011 for Mac and we recently migrated to Exchange 2013 on the server side. The problem appeared around the same dates. 

We do not know if it is related, because we did the test with their account on Windows Outlook 2013 client and everything is working fine, plus I personally use outlook for Mac and do not have this problem.

The only thing they have in common and I do not have is huge inboxes. One of them over 7000 mails.

Problem:
They do not get new mails unless they click SEND/RECEIVE. The workaround right now is to plan a SEND/RECEIVE every 5min. 

Done:
Already tried to flush the local cache and rebuild the Office Main Identity database. They do want to have a cached mailbox (not headers only).

Question:
If someone have any clue about what may cause this problem, please respond.
I have recently move from a windows environment to a Mac environment and moved my email accounts from Outlook on my old laptop to the new Mac Outlook 2011 in the .pst format. 
Since then, all emails, for all 3 accounts, have been coming into one Inbox. how can i have the emails directed to their respective accounts? The accounts are; 1 exchange and 2 hotmail (pop)