If an IMAP account is over quota, inbox and all its sub-folder turns into red. The problem is that they don't automatically turn black after deleting enough messages and account is under notification-limit again. "Download messages" and "Update folder and its subfolders" don't help, only going to the "Quota" tab on "Folder properties" dialog does the trick. Also a problem is that the subfolders don't turn black, I have to repeat going to the "Quota" tab on "Folder properties" dialog again to make them black. Reproducible: Always
*** Bug 314500 has been marked as a duplicate of this bug. ***
I can confirm this on openSuSE 12.3 with KDE 4.10
Moreover, after moving a "red" folder to a different account I cannot make it "black" at all. Even if I click on "Folder properties" and then the "Quota" tab, it remains red.
Move by dnd folder doesn't refresh quota. Bug knows (same for acl). It's not an imap resource bug but an akonadi bugs.
The IMAP resource has a new maintainer, reassigning to him.
I think this is fixed by now since metadata is now updated regularly. The necessary patches are currently in master only: 972cbee a4452f7