I NEVER THOUGHT I'D SEE THE DAY, BUT...
For at least 10 years there has been a documented "BUG" / "SECURITY HOLE" in Microsoft Outlook and the preview pane. Most people seem to like having the preview pane ON because as they click on each message they can see if it's worth opening, but what I have told my customers throughout the years is that if you use the preview pane it's just like opening an email.
What does that mean? It means if there is some hidden HTML malware code in the message, just by viewing it in the pane you are activating it as if you had just clicked on the message and opened it yourself, thus infecting your computer. As each version of Outlook came out many of us hoped that the hole would be patched - but it was not to be.
Well, next week around Tuesday or Wednesday Microsoft is finally releasing a patch that will, according to them, patch the hole. It's time to celebrate!