Currently Being ModeratedSep 24, 2013 8:57 PM (in response to peggybr)
I had this issue come up and for the most part it was fixed if you remove your current account and log back in. Unfortunately you will lose most of your folders (if you created any) and you will have to re-sync from scratch. Another possible solution is looking at your preferences and seeing if there is anything preventing attachments from being downloaded.
Hope this helps!
Currently Being ModeratedSep 25, 2013 9:39 AM (in response to kevbot96)
Try rebuilding the mailbox: Mailbox > Rebuild
If it doesn't work use this 2 lines in terminal :
defaults write com.apple.mail PreferPlainText -bool FALSE
defaults write com.apple.mail DisableInlineAttachmentViewing -bool yes