After users migrate from Exchange 2010 to Exchange 2013, some have complained that they cannot move elements by drag & drop in a specific subfolder of the Inbox and its sub-folders in Outlook. It does not affect all users and but can be replicated as required. Alternative also show that:
A look at the MAPI properties of the folders by MFCMAPI showed the following:
Manually setting the value of PR_CONTAINER_CLASS to IPF.Note for one of the "defective" folders immediately corrected the issue for that folder.