“With SP2, automatic background compacting was removed due to problems it caused. Now you will get a prompt to compact after 100 OE closings, which you should do and don't touch anything until it has finished. “
“You can't remove the prompt. There is a registry edit that you can do to set the counter to zero so you won't see the message again for another 100 closings.”
“Compacting your folders periodically is a must to keep OE functioning well and at some point, you may lose all your saved messages if you don't. When you delete messages, they are only marked for deletion and the space they had used, remains until you compact, or the space is eventually overwritten.”
“[highlight]Do not archive mail in default OE folders. They will eventually become corrupt and you may lose mail. Create your own user defined folders for storing mail and move your mail to them. Empty Deleted Items folder regularly. Keep user created folders under 100MB, and Default folders as empty as is feasible.”[/highlight]
“Just get this marvelous little program called OE Tool. Wonderful thing to have. It's free too! Button 14 will compact all folders and reset the counter to zero. This works better than the compacting in OE through Tools/options. You need to compact when OE gives you that message. Button 10 is great also. It clears the TIF OE files that are dumped there that otherwise are not cleared ever. I had over 9000 in there when I first got OE tool! I just checked again now...I hadn't used the button in awhile and I had 3589 files in TIF from OE that only will be cleared by this tool. I just love this tool.”
“OETool is great and I use it. However, anyone using an English version of XP/SP2 should make sure they have all critical patches, (at least), at Windows Updates, and then download this one that will also reset the counter to zero, as well as back up the dbx files when it does.”
Here is the site for the OE Tool:
http://www.oehelp.com/OETool/Default.aspx 
I have not used it so use at your own risk Alan <><
