User loses all his email after logging in from another domain

Just recently I have a user going to another office and logging in there to use Outlook 2003 to check email. This had been working fine until he forgot to log out of home office and logged in the other office. Now he can view all of his emails (old and new) in the other office but when he returns to the home office and opens Outlook he only sees today's emails in his inbox.....all the sent emails are current....all the emails in the delete box are current (I mean old emails are in there dating back months).......all previous emails in user's Inbox are gone......What is causing all of the user's emails in the Inbox to dissapear in home office pc?......

At first I thought it might be because he didn't log off but that really shouldn't matter....there is something set different on his home office pc...and for the life of me I can't find it.....

Any suggestions??

TIA

 

One of them set to leave copy on server and the other one isn't?

 

I've checked everything i know to check and i can't find where it would be set up to save the home pc to a local folder.....anyone know where you check that?