This may be a very elementary question, but here's the situation:
1 The user (the very non-technical user) is using Outlook 2007 on a machine running Windows XP Pro SP3, 4 GB RAM, 2.5 GHZ P4. She is accessing Exchange Server 2003 Enterprise SP2.
2 The user sends and receives a lot of mail. She has tens of thousands of posts in her inbox and thousands of posts in her outbox.
3 The user has set up a complicated folder structure in her inbox to try to keep track of mail.
4 On occasion, the user will be working away and will become aware that she hasn't got a new post in about a half hour, something quite unusual for her. She might also get a phone call indicating that some mail that she had sent out has not arrived. She will notice a smaill icon at the bottom of the screen indicating an error condition.
5 She then archives some mail, usually in the outbox. Within a few seconds she gets an avalanche of mail, as all the mail which had not arrived now shows up at once. Also, all outgoing mail which had not gone out is sent with the same time stamp. (I became involved in this when I got three posts from her which all had the exact same time stamp and asked how she did that.)
6 There does not seem to be a set number of posts in either the inbox or the outbox which will trigger this behaviour. There also does not seem to be a set size of her email database. However, this is happening more and more often now.
Does anyone know what might be going on? I'd suspect that the server is running low on space, but it's the Enterprise version, and that should be able to see 16 TB, which should be vast overkill for the user's company. And, besides, everyone else at the site uses the same server and no-one else is having this problem.