Fixing problems with outlook message stores

I was recently asked to look at a problem with someone's outlook.
Whenever they started it up it was trying to send 2 messages that did not show up in the outbox. It failed due to the security settings between the machine concerned and the email server. All other email seemed to work fine.
Using my usual research tool I found a few possible causes but the favourite seemed to be some read receipts that had got stuck.
I found some very helpful instructions at http://www.howto-outlook.com/howto/deletereadreceipt.htm which required a download from microsoft MDBVU32.exe.
This program looks as dangerous as regedit. I was very glad of the instructions on the referring web page which included screen shots. I think the program has been updated since the screenshots were taken though as I had to hunt for the option to open the data store. I was able to work out where I needed to be quite nicely though.
A useful tool to know about.