Basically there is no such thing as a message preview. The moment you highlight a message it get's opened and hence marked as 'read'. You can either mark it as 'unread' afterwards or disable the message pane altogether by pressing F8.

Thank you, christ1! I can set M$ to not count preview as "read" but since I'd much rather use Thunderbird, I won't worry about it.

Also, I have to apologize for posting; whenever I post a question in a forum, I always search first to see if the question has already been asked. And invariably, after I post, I see the answer that I asked. Sheesh. Not sure how to correct that.

There is a setting under... Tools-Options-Advanced-Reading and Display where you can set a delay to Mark as Read. That might help with what you want to do.

Hi Airmail, thanks, but that's not quite what I wanted. Basically, my concern was if I received a spam message, but I wasn't sure if it was spam or not...sometimes the spammers use a name that looks legit at first glance. I was worried that if I opened the message, then I was pretty much confirming that they'd got a valid email address. I wanted to be able to preview messages without them opening, so I could see if it was spam first.

Also, I just wanted to keep messages showing as unread so that I would see that I needed to take further action. Which can totally be accomplished by tagging them. Thanks for your help! I learned something new; I didn't know about that 'delay' feature. Could come in handy :)

Duh, okay; once again I post before I think. Airmail, that totally solves the spam problem.

Thank you!!!