I own the Photoshop Photography CC plan. I installed LRCC 2015 via the Creative Cloud application but it won't launch. The splash screen flashes briefly and LR dies immediately. I have rebooted the machine but no help.
The solution for most folks is to open their Creative Cloud App, click the gear, click Preferences, Sign Out and then Sign back in.
There is a crash on launch issue that the team has identified. If you installed third party Lightroom plug-ins, please check out https://helpx.adobe.com/lightroom/kb/lightroom-cc-2015-2-1-crashes-when-opening-or-opening-after-crea.html.