Thanks for the prompt reply. I've done some research, and Mountain Lion include Ruby 1.8.7.So, in your opinion, if I were to downgrade to Mountain Lion, would I need to reinstall SU, or would the problem probably be solved?

If I downgrade my OSX to, say, Mountain Lion, will that version include Ruby 1.8? And if so, will it fix my problem?

I have SU v13 on two Mac's computers. One is a MacBook Pro, and the other is on the MacMini. The program works fine on the MacBook, but my problem is on the MacMini. The program was installed on my MacBook before I upgraded to the Yosemite version. But I only installed the program on my MacMini after Yosemite was installed.

Is that what makes the difference? If so, can I corrected somehow?

Many thanks for your help.

When I click on Windows, this is what I get

Thanks, John. When I click on Windows in the Menu bar, There is no option called "Ruby Console"

I'm a newbie in SU. How exactly do I get into the Ruby Console?

SU is on my Mac-Mini, and I'm running Yosemite

Whenever I load up SU, I get this warning screen. Is there some simple fix for this?