Hi there: I tried this with Apple support. But it wouldn’t let me copy files, because it said I didn’t have permissions.
The permissions on my TimeMachine Backup sparsebundle fileare something like daapd read and write, staff is write only (dropbox) and everyone else has No Access.
It looks like this is an issue elsewhere:
http://community.wd.com/t5/My-Book-Live/Admin-account-permissions-issue/td-p/326599
