Hi Ralph. I've got a 2011 iMac, running 10.11.13, and recently experienced hardware failure with my very lightly used ColorMunki. The problem was with the physical dial. I'd turn it as instructed, but the on screen animation would show the dial turning to another setting, so I couldn't complete a print profile. While X-rite's customer support is quite slow (one response per day!?), in the end, they acknowledged this was a problem they've seen before, and even though my device was out of warranty, have agreed to replace it, at no cost. FYI, here in Canada the CM sells for over $600.00, thanks to a tanked Canadian dollar.
Curiously, I was never satisfied with the quality of screen calibrations, using the CM. Instead, I've achieved much better results using a Spyder 3 for hardware, and ColorEyes Display Pro for the software driver. For print profiles, though, the CM provides pretty darn good results.
Another solution that I'm still mulling over, is to go in for the Image Print RIP. While pricey, I really love the amazingly neutral B&W, that this provides. You're able to download the fully functional, but watermarked version, to try it out. Here's the kicker: If they don't already have your paper's ICC profile in their huge database, then they'll create one for free! Not bad. And keep in mind that they're probably using something at least at the Eye One Pro grade, or better, to create the new profile.