I've had no issues with SPSS 24 running properly prior to migrating the program to my new Macbook. I'm now getting "Error 13: You are not authorized." even though nothing has changed and I still have one more download left. 

Hello Grace,

If you move SPSS from your laptop to another computer, the app does need reinstalled and then relicensed on the newer computer. Do you still have the original authorisation code?