Hi, i just tried installing Reason 4.0 on my MacBook 1.83 GHz Intel Core Duo, Running snow leopard, 10.6. When i opened it up, it kept on unexpectedly quitting. I installed the 4.01 update, same thing. I repaired my disk permissions and cleared my PRAM, still nothing. Then i trashed the app support folder and the app itself and reinstalled 4.0, opening in "Rosetta" mode this time. This time it prompted me for my username and password, continued opening, then gave me error message:

Running Repair Tool Failed
Failed to start the repair tool. Terminating application.

What in gods name am i supposed to do?!

Well , i dont know anything about OSX , but i can ask around for similar problems ...

If i can find a solution , you will hear it right here ... (Unless you allready have found a solution yourself ...)

have you tried rebooting the machine?