Quick Tip to ensure your Photos never go missing To enable it, open 'Photos' app for OS X, go to 'View' tab and then select 'Show Sidebar' option. If you want to see a list of all your folders and albums, then enable the 'Sidebar'. So, if you want to merge albums in Photos for Mac, then you can select all the photos within one album and drag them into the other and then delete the first album. Photos for Mac does not allow you to drag albums into each other to merge them. But, in Photos for Mac, all iPhoto events are now albums. In iPhoto, you can merge events simply by dragging one event into another.
