(ahem - as I was saying) . . . day was a steady stream of EXC_BAD_ACCESS (SIGBUS) crashes.
I found this advice at http://www.artiss.co.uk/2012/11/exc_bad_access-sigbus-crashes-on-mountain-lion, being:
"I’ve just started experiencing EXC_BAD_ACCESS (SIGBUS) crashes when attempting to start Evernote or Komodo Edit and a minute after starting Chrome.
I had no idea what was causing this and looking on Google indicated everything from faulty memory to needing to re-install Mountain Lion.
However, it was only when looking for this error along with Evernote that I stumbled across something less radical that, thankfully, fixed the issue.
First launch Terminal.
Now run.
sudo update_dyld_shared_cache -force
Finally, reboot."
I followed this recommendation, and my various OSs have returned to normal.
Thanks again for your help.
