I recently had to use a backup Mac and found my favourite SSH tool, Coda (which comes with built-in SSH connections), was crashing when connecting to remote sites.
The solution was amazingly simple. From the Coda menu:
Sites > Show Sites
then just toggle Sites > Arrange by. I had it on None so:
Sites > Arrange By > Name
Sites > Arrange By > None
And bizarrely, that was the end of the my BBOD (otherwise known as a beach ball of death or spinning beachball of death).