There was a fix for R7 for Mac users...

[bitley]

...and I upgraded to 10.10.3 today. Reason 7.1 build 4948 runs fine on it.
Was something supposed to lock up / behave strangely with this Reason version on 10.10.3?

[Kazz]

The reason for the update is that the Codemeter stuff was changed in Reason 8 and if you had 7 and 8 both installed on a Mac you had to reboot and reinstall that every time you switched between them. The latest version of 7 fixes that.

[bitley]

Ah! Ok, good. I did actually have R8 installed but I removed it. For the time being I don't think I need what was added above R7.