When I start recovery 10.10 the loading never stops

Hello,

I have a MacBook Pro Retina mid 2012, 2.3GHz running on Yosemite and my problem is that when I turn my computer while pressing alt key, it shows me my three drives: Macintosh, Bootcamp and Recovery 10.10. However when I launch my recovery, a loading starts (the same as the one as when I start my computer) but simply never ends (I waited all night...).

Hope you can help me,

Thank you.