I haven't been able to run checkers for at least 3 weeks at this point using the OS/browser noted. However, after reading some other similar issues today, I tried using Firefox (57.0.3) on the same machine and I had no problem with the checkers. Is there an issue with Safari in general? Or maybe just with Apple products/software? I don't normally run Firefox, so this throws me off my game going this route. Since it appears that some fixes were published earlier today, and I still can't run checkers in Safari, I suspect that there may still be some pieces that were not addressed. What is the oldest version of OSX (different from iOS) that is currently supported? Thanks!