http://www.niksoftware.com/support/usa/entry.php?view=faqs/general_answers.shtml#Upgarde_t o CS6_do_not_see_plugins
General Product FAQs I upgraded to Adobe Photoshop CS6, now I don't see my Nik Software plug-ins. How do I correct this?
In order to ensure the Nik Software products are installed properly into Photoshop CS6, please click here to download the latest software updates. After downloading these latest versions of the products, quit out of Photoshop and run the Nik installers. The next time you launch Photoshop CS6 they will be available.
The license reverting back to Trial is a known issue we're investigating.
Creative Cloud products revert to trial mode with incorrect number of days remaining | CCM | CS6