I've been involved in quite a bit of a conversation with Robert recently who has been losing mails from Outlook 2003 when logged in over a VPN. When he logs in from his new machine, his messages disappear from the server and he can't access the mails from his other machines:
In the office if he accessed the emails they remain on the system
If he accessed the emails, using the VPN on his home desktop, they remain on the system.
The laptop however, does not act the same way, it is supposed to. By caching and sychronizing the mails it removes them from the server and stores them only on the laptop. The laptop is a new addtion to the system.
So what's been happening here is that Robert's mails have been delivered to a PST on his laptop which is moving the copy of the mail from the server, and leaving the mail on his laptop, where it's inaccessible to him from any other machine. So he needs to change the "Deliver new mail to the following location" setting Here's how you do this:
If you use Outlook with Exchange Server, you can choose to have Outlook store information on the Exchange Server or in a set of personal folders (.pst) file on your hard disk. Use the following steps to determine where Outlook currently stores your data.
1.On the Tools menu, click Email Accounts
2.Click View or Change Existing Email Accounts, and then click Next.
3.Verify the Deliver new mail to the following location. option. If the option contains the word "Mailbox" followed by an e-mail name, Outlook stores data in folders on the Exchange Server. If the field contains the words Personal Folder or another name of a set of personal folders (.pst) file, Outlook stores new messages, contacts, appointments, and such in the personal folders (.pst) file on your hard disk.
So now all Robert has to do is select the correct option (his mailbox) and then move the mail back from his PST on the laptop back to his inbox folder on the server (Right click and move messages to the folder you want), and they will then be available to all machines, whether on or off the network..
Here's a KB article (for Outlook 2002 but still useful) which tallks about moving data between PST's and the folders on the server...