I recieve a few regular emails that are sent in html format and these have always arrived just fine, but I recently noticed that they were arriving in plain text form... or so I thought.

The size of the message is the same, the html can be seen when using 'view original' and old messages that used to show html now show only text.

I've looked in bigzilla and I've looked at the preferences incase I've turned something off but I find nothing, any ideas?