Thanks for that - I've just checked that folder, and it's only 375MB in total, across all my folders. This seems more or less right, if I look at my actual emails in my folders, inbox etc.
Compacting is less about saving space and more about cleansing the databases.
I don't want to compact, though. I want the message to compact to go away. One day I'm going to click it by mistake, and that's going to irritate me bigtime, because I don't want to have to spend time setting it all up again...
Setting what all up again?
How do I get the message to go away? Where do I go to change this setting?
It is rumoured that the message is triggered by a registry value reaching 100 *but* I don't know that this is definitely true therefore I don't know the impact of changing the value. If you run a Google search for Compact Check Count, you'll find the relevant information and can decide if you want to proceed in taking a chance in changing the value.