Problem (bug?) deleting folders in Outlook 2013

Doing some tidying up of a mailbox the other day, and wanted to delete some empty folders from the Deleted Items (i.e. permanently delete them). For some reason Outlook gave me the following error:

Opening up Deleted Items and trying to delete each folder in turn gave me this slightly different one – but equally frustrating :

Attempts to permanently delete the items (using SHIFT and Delete) drew a blank – same problem.

Playing with the folder permissions (via the properties pane) – no joy.

Clearly this is a bug in Outlook (and not anything I was doing wrong). Workaround was to log into the mailbox using Outlook Web Access (OWA) and trying it from there – no problem.

It would seem that the synchronisation logic that the full client uses is buggy – it’s useful to remember that you can sometimes do things in OWA that you cannot with Outlook if you run into trouble.