Are you on Windows?
If so, is there any chance you were using the 32 bit version of Photoshop and are now running the 64 bit version, or vice versa?
I ask, because 32 bit plug-ins only work with 32 bit Photoshop, and 64 bit plug-ins only work with 64 bit Photoshop.
i only installed the 64 bit versions (both - creative suite as well as the plugins) - when I go to the folder plugin and start any *.Ink, photoshop is starting and will show all plugins correctly. When I close Photoshop and start photoshop again, plugins are disappeared. What I don't understand, I installed the same constellation on my laptop, also win7, here are no problems.
When you install CS6 and CC on a 64bit windows system both the 32bit version and the 64bit versions of Photoshop are installed by default. In CS6 there is an option not to install the 32Bit version but that is not an option in the CC installer. You could be starting the 32bit version when your not seeing the Plug-ins. For the 32Bit version of plug-ins are installed into the 32bit Photoshop version install tree. Check your start button how many Photoshop start icons do you have. Also make sure ant short cut icon you use to start Photoshop is starting the right version exe. Also make sure that file associations for image files are for the 64bit version not the 32bit version.
thanks, I found the mistake. I installed photoshop cs6/64 twice on 2 different hard disks. sometimes it seems to be blind ...