I'm going round and round trying to future proof myself with cleanersmate. I'm still on my first installation so have a licence key spare but no download file or disc.
Trying to export all the customers to a .csv will depend on whether you have opted them in/out of your mailing list. This doesn't transfer any history, invoices or quotes as far as I can manage. Not sure if moving it to GBU transfers everything but I don't really want to go down a subscription model.
If anybody has a disc I could buy / borrow I'd be happier as the software itself does everything I want. I'm on v 3.1.7.0 if that isn't being too picky!
v 2.something is downloadable but you still need a licence key so won't help your original problem.