Script Editor on El Capitan giving me unfixable, recurrent spinning ball

Context: updated El Capitan, recent MacBook Pro with 16 GB RAM, Script Editor 2.8.1 application:

I had several scripts and Preview.sdef open and had been working for a few hours, including saving scripts, without incident and tried to save my work on a new script and encountered the spinning ball. This happens occasionally, requring Force Quit. So I Force quit. Try to reopen script editor: immediate spinning ball. Restart computer. Try to reopen script editor: spinning ball again.

i.e., I am not unable to open Script Editor.

Any thoughts on how to troubleshoot appreciated--

William