[X4U] Mail.app Mailbox Messages Message?

[David R.Boag]

I am getting the following message ever since I put my emails into a 
certain folder: The message from [sender] concerning "[subject]" has 
not been downloaded from the server. You need to take this account 
online in order to download it.

I have already DL'ed these messages, and there are literally thousands 
of them. There's got to be a simple solution.

Do I just rebuild the mailbox? Any further suggestions? The message 
list still tells me how many attachments there are and everything.

Thanks.