Attachments disappear when sent

[Gnougat]

I'm in the process of looking for a job, so I regularly reply to job ads and send emails from Outlook, using my Gmail account, with my resume and cover letter attached as word documents. The recipients always receive my emails, but they don't necesserily receive the attachments. Sometimes they do and it's fine; some other times employers reply saying they could not open the attachments - and what they mean by that is, my word docs were not in the email they received, all they see as an attachment is winmail.dat, and they just assume that is my resume submitted in a weird format they can't open. Each time I've received such emails, I've checked the message I orginally sent, and they always looked fine, the word docs properly attached and opening well.

Does anyone have a clue as to why the attachements just don't reach some of the recipients? I thought maybe it was their settings but it doesn't make sense; as recruiters they're expecting to get attachments sent from Outlook and wouldn't be blocking them. If you have the answer, I'd be thrilled to hear it! There's no way I'm going to find a job if the recruiters don't receive my resume...