Not sure what to classify this problem as but it took a long time to resolve so I wanted to blog it. My outlook 2003 was running very slow. Used 98% system resources whenever I opened or created a HTML email. I ran virus tests, rootkit test and anything else I could find. Eventually I just learned to live with it because after an hour or two it would behave normally and if I didnt turn my computer off it was ok. I reckon 6 months I put up with it. Then one day after it wouldnt fix it self all day I raised a job for one of our engineers to fix it. Martin tried a few things that had no effect, then on the second round of attempts he found that the restricted sites under the security tab in IE options had thousands of sites listed in it. Apparently outlook (and word) scan html documents for restricted sites and hence the slowness. Removing the restricted sites list fixed the problem. It was always one of the first things I did when I ran spybot to scan for spyware was to run their immunize option. Apparently immunize adds thousands (6000+) of sites to the restricted sites list. Leason learned.