Why are Outlook emails opening in .txt not .html?

I have Outlook 2007 on a Win7-64 Pro.

Several regular emails are now opening in a .txt format instead of their usual .html.

How do I fix this?

 

retiredlearner,

Thanks but the Compose setting was already set to html. I temp changed it to Text > Apply and then back to html > Apply hoping that would do something.

Maybe I have to wait for certain new emails to come in to check but the recent old ones are still in text format.

 

Did you Shut down and Restart comp after making the changes?

 

retiredlearner,

Thanks, your suggestion solved the problem for one of the two sites that came thru in text.
The second forum site's email is still in text but if I look at it thru the site and not Outlook it is in html.

Still haven't figured that one out.

 

retiredlearner,

The site that was fixed is not back to text format and the one that was never fixed is still text.
I checked Outlook and it is still html (I reboot every day).
Outlook > Tools > Options > Mail Forum > Message Format > Compose in this format = html.

Any other suggestions would be appreciated?