Webmail and attachments

Like most IT pros, I have the priviledge of supporting family members whenever they have computer troubles. I was recently at my in-laws and they have an interesting problem that stumped me.

They're using a webmail service for their email. Whenever they attempt to open an attachment through IE8, they are unable click on the 'open the attachment' option in the dialog. They have to save it to disk first, and then they can open it. If they use another browser, like firefox, it works fine.

I suspect it's because IE8 doesn't trust the webmail site, but I can't figure out how to get it to work. I've already tried adding the site to the trusted sites list with no effect.

Any thoughts?

The "Medium High" Security level "prompts before downloading". They could try a lower level or a customized level. Or, if they changed the default settings, the could restore them by doing a reset: Tools/Internet Options/Advanced/Reset. (I don't know if the default settings are low enough though.)