There are many, many differences between CS6 and CC. They should coexist peacefully, so you should not need to uninstall CS6. In fact, if you have use for Encore, then you should not uninstall CS6 or else you'll lose that program (until you reinstall CS6, which you can do through Creative Cloud...)
Several people have found that updating their graphics card driver resolves the crash on startup. A few others had to update the driver for their processor.
Let us know if neither of those measures work and we'll dig deeper.
As you mention, an obsolete video driver is one of the main causes for PrPro to not launch (all versions).
I strongly recommend that any user, who thinks that that might be an issue, go to the video card's/chip's mfgr's Web site, and manually check for video driver updates. In the case of some major computer mfgrs., like Dell, or HP, it also pays to look on their Web sites, as some mfgrs. will repackage the video drivers. I strongly recommend that a user not rely on their Windows OS, or any driver utility to tell them, if they have the latest video driver - check that manually.
For a Mac, the video drivers are usually included in the most recent OS updates. Not sure if that is 100% correct with PrPro, CUDA and supported cards, as I am a PC-only guy.
Very good points, Bill. Your contribution also reminded me that some PPRO users have reported with the current Nvidia drivers (version 320.xx). We recommend version 311.50.
I have not uninstalled cs6 and it loads and works fine. I will check for driver updates. Thank you
Just got around to downloading the latest driver. Works great. Thank you for your help.