I've just upgraded a site from 4.x to 7.1 and all works good except that the media picker won't browse a particular media folder which has several hundred items in it. The returned JSON looks good in Firebug though it is so big it has to open the JSON in a new window.

Is this a known issue? What is the work around? I can't move each media item to a new folder indivdually as will take forever. Is there a way to bulk reorganise media items?

Thanks

Dan