I had the same problem, nothing happened and no message. Console didn't show anything either. I checked and did have the latest versions and all updates.
What worked form me was to trash, and empty, iPhoto. Then I went to the app store, chose the purchases tab, downloaded and reinstalled it. Now it works! For how long, that will be another discussion soon to come.
Funny thing is, I tried the developer releases of Yosemite and never had any trouble. Apple really needs to get back on track and test these things before releasing them. It feels like they only test things on new hardware and fail to test thoroughly.