A brief window saying "ButtonLibrary.indl" cannot be found, followed by "Adobe InDesign is shutting down. A serious error was detected. Please restart InDesign to recover work in any unsaved InDesign documents." However, InDesign will not restart without the same crash sequence. Help! (Please?)
Try emptying the recovery folder.
It turned out to be problems with the plugin FontGazer, which I removed -- after that all was well.