Apple Preview>File>Open won't open Aperture 3.6 Projects/Albums so I can access an image to put a caption onto it

I use Preview to open Aperture so I can put captions on images I've finished editing in Aperture 3.6. However, often the Gear symbol in Preview "File>Open" keeps spinning without ever opening Aperture. Therefore I cannot select and Project or Album I want to open the select photo I want to work on.

Any ideas ?

Aperture 3.6 on a MacBookPro with Yosemite 10.10.5.

Thank you