Stan W writes (NB. edited for brevity):

Over the last couple of days I have started using your great book with my two sons (13 and 15 years old). I'm reaching out to you with the following question because I have noticed other people asking about the same issue online, with at least one mentioning your book, so I think you posting the question and answer to your blog might help other people in addition to me and my sons.

We are using Mac OSX and have installed Python 3.3.3 from, and are getting this message when opening IDLE:

"WARNING: The version of Tcl/Tk (8.5.9) in use may be unstable. Visit for current information."

I have installed "Mac OS X 64-bit/32-bit Installer (3.3.3) for Mac OS X 10.6 and later" (file: python-3.3.3-macosx10.6.dmg) and installed the "ActiveTcl 8.6.1 for Mac OS X (10.5+, x86_64/x86)" (file: ActiveTcl8., but IDLE keeps showing the same error message.

Thank you very much for any help you can provide!

I'm not convinced ActiveTcl 8.6.1 is the right version to install - I suspect rather than installing the latest and greatest, you should be using version Python (and thus IDLE) will probably be using the latest 8.5 version of Tcl/Tk (i.e. 8.5.x) — you're installing a completely different version (8.6), which it's not looking for at all. Hence even though you think you've re-installed, you'll still be getting the same error message.

Hope that helps.