I've just upgraded a Civi 4.6.18 install to 4.7.15. All has gone fairly smoothly, apart from the fact that the CiviCRM front page/dashboard is broken.
My Firebug console reports: "TypeError: widget.name is null" and refers to http://siteroot.com/sites/all/modules/civicrm/js/jquery/jquery.dashboard.js line 467 col 13
I know that some of the dashlets that display in my dashboard have been created by setting up some reports to suit, and simply making those available as dashlets.
Looking in the database, I checked the civicrm_dashboard table, and noticed that three of these 'custom' dashlets had NULL in the name column. Interestingly, other similarly created dashlets had an entry in the name column of the form 'report/xx'.