After starting Jenkins, and clicking the "Open Blue Ocean" the progress bar gets stuck at appr 85%.  Submitted new bug here as requested by halkeye. The Java console shows a number of errors, eg:

"Error initializing Jenkins JavaScript bundle "blueocean-core-js" Error: Unexpected error executing startup module "../tstemp/js/bundleStartup.js": Error: Must call ExtensionStore.init"

 Log is attached as blueocean_stuck_20190321.log