MuseScore crashes on selecting and deleting selected measures.

Strange new problem. At first, I tried deleting about a page of my score by selecting the measures and using the Delete Selected Measures feature in the Edit drop-down. It worked the first time. I had more to delete and subsequent trials resulted in crashing. Interestingly, the score title did not appear in the "Recent" list of files. It had appeared, earlier. As I've tested this, I've completely shut down MuseScore and restarted it. I've also rebooted the computer. Nothing helps and now the crashing occurs on the first attempt to delete even one measure.