[X4U] Problems restoring backed up files to Apple Mail application

[Peter James]

I had a problem with the Apple Mail application where I accidentally  
deleted the Sent Mail box.  I was not worried as I had done a back up  
some three days earlier and I was able to copy across from the backup  
CD to Library/Mail/Pop-my-email-address/Sent messages.mbox all of the  
missing sent mail. There was no problem in installing the missing  
files, but Mail will only display them for a short time, and then  
refuses to display them.  I've checked and they are still in the  
correct directory but not showing in Mail.  I've repaired  
permissions, but this doesn't make any difference.