outlook email text only message to rich text format

They had two addresses for me, one from their server to an exchange server that forwards to a normal ISP POP3 and my direct one. Then it suddenly started happening when another organisation was sending me e-mails. Bottom line I had learnt to live with it :-(. Thank you very much for your contributions and I will pull my weight by working through this. Hey, really sorry to have left this thread alone. So By using 'use default', I would have expected it to use Outlooks on the sender, which it isn't. This Setting (Was: Use Default, now Always) Recipient Domain settings if set (I haven't set any up for jac2 as far as I am aware)

I checked in Exchange Management Console | Mail Contact | General and the only thing I could find is 'Use MAPI rich text format': Use Default Settings, which when I look at the help said it goes, in order of priority:

I checked the settings on the senders outlook (via exchange) Options | Mail Format | Message Format = HTML

and it finds me in their MRU then it is fine.

If people select that contact as a recipient rather than putting in my e-mail address then e-mail gets converted to plain text, if they start typing jaso. I had set up my external e-mail (me) as a 'Mail Contact' in exchange. It seemed random, but early this morning after replying to someone saying they had removed the formatting to me, I realised what was going on. For a while I have noticed that e-mails that users send out (Outlook 2007, MS SBS 2008) to me have ben losing formatting, but not all the time.

Outlook email text only message to rich text format