Hi, this is an issue that some Mac users run into, but so far we've been able to get it running for everyone eventually.
Try these steps first:
1. Open a window in Terminal.
2. Type or paste sudo chmod -R 777 into the Terminal window
3. Add a space to the line, and then drag the game file directly into the Terminal window, where it should add the file path to the text
4. Hit return/enter and you will be prompted to enter your main computer password.
5. After confirming your password the permissions for the game should be updated and it should be able to run.
Let me know if that works for you. Sorry for the inconvenience!