Color was last updated 5 years ago, and was discontinued 4 years ago. At that time 10.6.8 was the OS it ran on. Since it was discontinued, every OS update doesn't take into consideration, it or any other discontinued app into consideration....doesn't ensure they will work. Nor are the apps being patched to ensure that they work. So every OS update is yet another chance at breaking the functionality of older apps. Looks like you hit that break.
I keep a MacPro Tower with a 10.6.8 partition for just this reason...to work on client projects that still require me to use FCP 7 and Color and the other Pro Apps.
The only thing I can suggest, if you need this to work, is not a simple fix. You need to back up your hard drive (clone it perhaps, to make sure you get everything) and then wipe your hard drive, and install, from scratch, an older, supported OS. If it worked under Mavericks, perhaps that (that's where support stopped for me, when I used this on my laptop). And keep it there. Or partition your hard drive (you can do this even if you have stuff on it) and install the OS and those apps on a smaller partition, and keep that partition only for those apps.
Sorry, that's all I have. El Cap broke a lot of apps...even the current versions of Premiere Pro and Avid don't work under El Cap.
