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

then

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).