Failed import from iPhoto to Aperture - what's the best solution?

Question

Hello
After some years of using iPhoto I recently upgraded to Aperture 3.2.2.  In connection with that and before opening Aperture, I bought a new external hard drive and moved my iPhoto library to it, following Apple's instructions on how to move an iPhoto library to a different drive.
When I opened Aperture and was given the option to import my iPhoto library (of some 30,000 images), I chose, because I thought it was safer, to allow Aperture to access the images in my iPhoto library as referenced images rather than to store them in the Aperture library. 
Unfortunately, the import was incomplete.  I decided to try to import again, in the same way, to see if that would result in my having all of the iPhoto images.  The re-import was also incomplete.  Worse than that, although I had told Aperture not to import duplicates, it imported for a second time many of the images that it imported the first time.  I now have in Aperture two separate large but incomplete iPhoto libraries.
After this, I learned that before using an external drive with Aperture I should have formatted it to Mac OS Extended, which I had not done.  Other research I have done suggests that a surprising number of people have significant problems in trying to move iPhoto libraries to Aperture, but I have not found a case that addresses my problem.
My idea now, subject to any advice anyone can give me, is to move the iPhoto library back to the Mac's hard drive (there is enough room, but little spare), delete everything on the external drive, format the external drive to Mac OS Extended, re-organise some of the iPhoto events, 'delete' the 'contents' of the Aperture library (without affecting of course the contents of the iPhoto library) and try again (possibly by importing the iPhotos this time on an event by event basis).
Is this a good idea?  If so, I would be grateful for any suggestions about how to take these steps.  In particular, the step of deleting the contents of the Aperture library without affecting the iPhoto library.  Are there other better ideas?  If so, what?
Thanks very much in advance for any help anyone can offer.

Answer 1

My idea now, subject to any advice anyone can give me, is to move the iPhoto library back to the Mac's hard drive (there is enough room, but little spare), delete everything on the external drive, format the external drive to Mac OS Extended, re-organise some of the iPhoto events, 'delete' the 'contents' of the Aperture library (without affecting of course the contents of the iPhoto library) and try again (possibly by importing the iPhotos this time on an event by event basis).
If there is nothing in your Aperture library that you need to keep, that is a good strategy.
But some suggestions:
Before you move your iPhoto Library from its current location (which will render the Aperture library useless, because it is referencing inside iPhoto), check if you accidentally have imported any images as managed into Aperture: create a smart album with the rule "File status is managed" at the top level of the library albums. This way you will see, if you have any images only in Aperture, that need exporting, before you delete the library.
Also right now the best option to import from iPhoto into Aperture is by importing complete libraries, not single iPhoto events or albums. If you import Libraries, Aperture can combine the iPhoto Originals and the edited versions into "Master-Version" pairs and save considerable space. This is only possible by importing the complete library, for more deatails see this recent thread:
Correct Answer Re: Aperture Loses iPhoto Edited Images
I advise against referencing the masters inside iPhoto, for it is risky. If you open iPhoto and accidentally edit or modify the referenced master in any way, then the reference will be broken. It would be safer by far to create a backup copy of your iPhoto Library and to import the image files into Aperture or to relocate the imported files as referenced masters somewhere else, after you imported them.
Post back, if you have more questions.
Regards
Léonie