Rekordbox not loading

1) Operating System: OS X 10.12.5
2) OS Type: 64bit
3) rekordbox version: 4.3.1
8) Is rekordbox crashing at all: No 
8b) If not crashing, are there any error messages: No 
9) Are you able to repeat / reproduce the problem: Yes
9a) If yes, can you do it consistently: Yes
12) Provide as much detail of the issue here:

I recently migrated to a new MacBook pro 2016 touchbar. I use the internal drive for my music productions and set up and external bootable ssd drive via a thunderbolt 2 connection with mac OS 10.12.5 for my so called office work. This external drive was carbon copied from my old MacBook pro and contains all my music files as well as rekordbox. 

When I click on the rekordbox application, the program briefly starts reading tracks then stops responding. I get the rekordbox (not responding) message and nothing further happens afterwards. I tried uninstalling it with clean my mac 3 and reinstall the program but the results are the same. I installed rekordbox on my my internal drive and was able to successfully use it. It did ask me to change the tag to this computer which I did. But no luck on the external drive where i want to use the application.

Thank you for your help.

Stephan.