When I start BaseCamp i get the spinning beach ball displayed but do not get any further. This happens regardless of a GPS being connected to the computer or not. Any help much appreciated.
Yup! This is what was causing the problem for me. I had a permanent connection to my network connected Time Machine backup and this was causing problems for BaseCamp. Once I removed this permanent connection, it works fine.
The problem did not exist in BC 4.0.1. I'm not sure which version introduced the problem.
The issue with Time Machine volumes hanging BaseCamp should be fixed in the upcoming 4.2 release. Please tell us if the issue still persists, but we were able to recreate the issue and verify that it no longer freezes.