As an Aperture&#x2F;iPhoto&#x2F;Lightroom user, there _is_ a perfectly viable way to test this out. First, find your iPhoto library, then copy it to an external drive. then, attempt the iPhoto upgrade. iPhoto libraries are self-contained, as are aperture libraries, so you can very easily duplicate folders. I suggest you run a library rebuild through iPhoto before copying it, and if you want to be extra sure, I also suggest moving it with a utility that can tell you if certain files have errors while copying. In the past, I have found Ditto to be pretty good for this.<p>I did this recently, as every few months I take a complete copy of my aperture library and migrate it to an external drive which I keep off-site at a friends house. He, in turn keeps his library at mine. The overall point is that iPhoto &gt; photos is fairly trivial to test it out, and see how it works for you. (PS. this is even easier if you have enough space to just duplicate the drive in-place. If you do that, though, I still recommend library rebuild before duplicating.)