Situation: Exchange 2007 has a contact (not a mailbox) within the GAL that end-user use to email instead of using the actual non-exchange email address. The non-exchange (network solutions) user does not get attachment sent (Word, Excel, etc.), but does get a winmail.dat file attached.
Fix: Launch Exchange Management Console, goto Recipient Configuration/Mail Contact container, open up contact you’re having the issue with, on the ‘general’ tab change the ‘Use MAPI rich text format’ drop-down to ‘Never’ and test.
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