Hotmail seems of late to be changing it's rules, without warning it's users - nice.
The latest of these that I've noticed is that your sent messages (in your "Sent Messages Folder" will only be kept for 30 days ... OK I guess, but thanks for warning us ... they've deleted a bunch of old mail that I wanted to keep!
This may well apply to you too if you have a hotmail account - I'd create a new folder called "Real sent messages" or "Messages I wana keep" and move them there ...
anyway ... good luck,
Mike
PS I'm back from my hols now, and need to catch up ...