Created attachment 8673869 [details] TB_Daily.PNG User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:41.0) Gecko/20100101 Firefox/41.0 Build ID: 20150929144111 Steps to reproduce: Removed TB Daily and reinstalled my saved copy of thunderbird-44.0a1.en-US.win64.installer.exe which has update 2015100830223 applied already. Daily starts and populates all of the panes and Lightning is available. Actual results: When the "New update" screen is displayed and, I choose to "restart", Daily will shutdown and I'm asked to allow the install to proceed. When Daily restarts none of the mail panes are populated - all are blank and Lightning will not start. Expected results: All mail panes should be populated and Lightning should be available.