After having Expandrive stop working with version 5.4.2 for Mac, I contacted Expandrive, and they just sent me a test build of 5.4.3 and it works again. It seems one of the libraries they updated had a processor based incompatibility that was only effecting a very small amount of people and I was unfortunately one of them!
Glad it is fixed, I had no idea how much I had come to rely on it!