Starting with OS X Yosemite v10.10.3, your Mac now includes the Photos app. If you were using iPhoto before updating, here’s more information about upgrading to Photos on your Mac.
When you install OS X Yosemite v10.10.3 or later, Photos for OS X is part of the update. In many cases, if you had a single iPhoto library in your Pictures folder, your entire library — including your photos, videos, projects, albums, and so on — automatically appears in Photos the first time you open it.
If you have more than one photo library on your Mac, then Photos will ask which one you want to upgrade the first time you open it. Photos allows you to open and work with libraries created in iPhoto.
- open Photos.
- Select the library you want to open and then click Choose Library. If the library you want isn’t listed, click Other Library. Navigate to the library you want, and click Open.
You can also drag the library you’d like to open to the Photos icon in the Dock. Or you can click Create New to create an all-new, empty library..
Let me know if this works for you please.