Desktop software works only first time after its installed

Please can somebody help me

I am working from a mac book pro an I have a strange issue with the BDS, the software will only connect with my phone on the first try after it has been installed, as soon as the phone has been disconnected from my mac then the BDS never recognises it again, it is becoming very frustrating as if I want to back up my blackberry I have to re install the software from scratch.

Does anybody have any solution to this annoying issue?

Thanks so much in advance

David