Hi-- I'm not sure if this question belongs here but here goes--lately I've been getting emails from a friend with attachments with a ".dat" file extension. What is a ".dat" extension, are they safe to open and if so, how is it done?

Not too long ago I had to get some major help from rridgely (thanks again) to get my computer cleaned up so I'm being uber-careful about what I open but I'm also curious what these are.

Any help would be appreciated. Thanks

If you don't know what it is, I wouldn't mess with it. I don't see any reason to run .dat files if you don't know why.

Your friends PC could easily be infected therefore asking them if they're responsible for attaching the .dat files is something to do. If they aren't then it would be a good idea for them to post a hijackthis log. Like TwistedMetal stated, those files aren't worth the risk to open hence you don't know what you're getting.

By any chance are these attachments "winmail.dat"?

If your friend is using Outlook as an e-mail client and using Rich Text or HTML format, Outlook attaches this formatting information file.

If you use Outlook as an e-mail client, it works in the background and you won't see the attachment but if you're not using Outlook, it appears separately.

Ask your friend to send a message in Plain Text and if no attachment appears, that is the explanation.