Now, I'm a complete n00b to Outlook 2007 administration, but after deleting a whole bunch (thousands? more?) of automated alerts, I decided to try a more immediate solution to tame my 2.2GB inbox PST. My first course of action was to compact the PST, via the Data File Management dialog and clicking on "Compact Now" for the correct inbox.
This may have been mistake #1 (perhaps the only mistake), but after a period of about 30 minutes, I hit 'Cancel' and figured I'd wait until the end of the workday. By this point, the size on disk of that inbox' PST was 3.2GB. Uh oh. Any subsequent attempts to compact the file have taken about 10 seconds to process, and not much happens. I've been checking activity via FileMonitor, but there are only a handful of reads, writes, and flushes to the PST, and the file size remains the same.
Finally, I tried forcing an archive of the inbox, and while my Archive.pst grew by about 500MB (I rarely archive, and don't have autoarchive on), Outlook.pst will not budge in size.
Any thoughts as to what I can do, or at least what I did wrong (feel free to chide me!)?
Edit: I'm not sure if it's relevant, but this is just against a POP3 server, not Exchange.
Edit^2: So I ran ScanPST in Program Files\Microsoft Office\Office12, and it did find errors that required attention...but the net result is that, without Outlook running (and thus receiving more mail), the PST file grew another 100MB.