If velocidrone stops on the loading screen it is because it is either unable to send data over your network or it cannot receive data over your network. Both issues are caused by your firewall or your antivirus products.

Velocidrone.exe should be granted both read and write access to your network in order to be able to check and verify your license at startup. If this is not possible it will hang as it cannot verify your credentials to run the program.

On both windows and Macs this can also be caused by running the sim from the downloads folder as many security products block network access to applications run from this folder.