That is because LR version CC 2015 and version 6 are exactly the same program. The difference comes by how you Sign In with an Adobe ID.
If you use an Adobe ID that has a valid, paid up, Photographer plan subscription it becomes the CC version.
If you sign in with an Adobe ID that is not associated with a subscription plan you are then asked to enter a serial number and it becomes the 6 version.
I have asked this question in one context or another many times over the
years. I appreciate that you have finally given me an answer that makes
sense and tells me what to do. (No tech at any level has ever done that.
One wonders if they even know this.) I'm going to try removing 5.7, which
I don't want and see if it helps. If not, I'll write again.
Meanwhile, many thanks.
email has been sent from a virus-free computer protected by Avast.
On Sun, Jan 24, 2016 at 10:21 PM, Shootistbond007 <firstname.lastname@example.org>
The following is just for your information for the future. I uninstalled
5.7 (CC Cleaner doesn't seem to apply). Then restarted the computer, of
course. Not immediately, but after several minutes an update became
available, and the program is back to normal. This is fine with me,
assuming I can always download LR 6 should I ever need it.
It would certainly be helpful if the information in your message was
available (and find-able) by using the web site's search function.
Again, thanks. I've marked your response as Correct.
The headline question was "How can I tell LR 6 from LR CC?"... If you go to the Help menu > System Info, then it will tell you which version you are running.
As ShootistBond pointed out above, it's actually the same exact download and installer, but it does different things depending on how the software is activated.
If you have Lightroom CC installed on your machine (say as a free trial), but want to convert it to Lightroom 6 instead, then you can follow the directions here: