Which version of mac os x are you using?
Adobe hasn't bundled the dng converter and camera raw plugin together for quite some time.
I don't know why adobe doesn't state that clearly, but they don't, which leads to confusion.
So what you downloaded and installed was just the 8.8 dng converter, which is in Applications>Adobe DNG Converter.app
It's a separate application to convert camera raw files to dng copies, which then can be opened in adobe photoshop cs to cc 2015
using the existing camera raw plugin.
For photoshop cs6 go to Help>Updates from within photoshop cs6 to download the camera raw 9.1.1 plugin update.
Then your nikon D5500 files should open directly into photoshop cs6.
If your using mac os x 10.6.8 snow leopard, then unfortunately photoshop cs6 can only be updated to camera raw 8.3
And one can only use up to the 8.3 dng converter as well.
Thank you so much! Yes, would have been great if Adobe had explained just a bit. Spent a couple of hours not getting anywhere this am. Anyway that worked fine. I now have acr9.11 and until I get another new camera I should be OK....
BTW, I have Mountain Lion. I'm thinking about upgrading to El Capitan but don't know if my CS will be happy - I have CS5.5 except for Photoshop which is 6. I remember when Mavericks came in, there was discussion about photoshop not working right, so I just ignored all the upgrades from then on. Would you happen to know I'd be safe installing El Capitan?
I'd wait at least until apple issues the first update 10.11.1 for El Capitan. and then peruse the adobe forums and see what if any improvement has been made as far as adobe applications working on El Capitan
There are major issues with some of the cs5/cs5.5 creative suite applications like Ilustrator cs5 on El Capitan, but photoshop cs6 runs okay with a few minor issues.
Thanks. I'll do that.