Importing an iPhoto library in Photos I had an iPhoto library in a non-standard folder and it was not recognised by Photos (which is OK).

I would now like to import all the photos and then delete the old library. How?

If I open Photos with option I can choose the iPhoto library. Will this copy all the pictures?
If you have an existing Photos library and you want to import an iPhoto library use File -> Import (shortcut: cmd+shift+i) and select your iPhoto library.

If you want a Photos library with just your old iPhoto library, hold alt (option) while starting Photos and select your iPhoto library.