I have this randomly happening to Inbox and Sent messages that previously worked perfectly.
It's a common problem.
I have it occuring on a Macbook Pro with Lion (10.7.4) and it randomly occurs with POP, IMAP and iCoud accounts. Been trying every recommendation, but have not found anything that works...
Uninstall Mail Add-Ons
Reload OSX Lion
Mail that I have viewed, saved and even forwarded to others in working condition, meaning messages that previously had funcitonal Attachments are now useless. It is there as a RAW SOURCE encoded image, and shows up as a # Qty of attachments next to the paperclip... but no way to View, Save or Forward those messages today.
I'm having the same problem, including the RAW data version (though this doesn't always appear).
If I look on the mail server directly (using webmail on the host), the attachments are there and intact, able to be downloaded.
OS X 10.7.5
Mail Version 5.3 (1283)
In all cases I've experienced, the attachements appeared originally, but no longer appear.
Wish there was a way to re-download the message from the server. Tried "syncronize (folder name)", but no luck.
Edit: there is a way to re-download the entire enclosing folder:
- highlight the parent folder for the message
- in the top menu, Mailbox > Rebuild