There are 3 possibilities here I can thing of. Seeing as you have imported from iPhoto I am thinking #3 is likely. 1. Duplicated Files 2. Versions 3. Multiple kinds of copies.
1. Duplicated Files
First thing I want to know is if we are actually feeling with literal duplicates. If that is the case, than some if the ideas in this topic may be helpful:How do I delete duplicate photos in iphoto as opposed to having to delete duplicates individually?just a reminder that any automated solution is going to have risks of removing something you didn't intend.(just a reminder that any automated solution is going to have risks of removing something you didn't intend.)
To know this you need compare the info for several of the duplicates. Do they have the same file name (and feel extension), file size & resolution?
2. Versions
Second, is the version name the same? Is the project path the same? If it is I think we are dealing with versions. If not, we are likely dealing with literal duplicated files on the hard drive.
If we are dealing with versions, then they are all referencing the same file on the hard drive. And the first question is are they stacked? From the top menu bar chose "Stacks>Close all stacks". If they are versions, the duplicates will disappear from view.
3. Multiple kinds of copies
If neither of these is the case, than what I think happened is that Aperture imported every photo from the iPhoto library file structure, and you likely have 3 or 4 copies of each photo (The original, the preview, the thumbnail and maybe an edited version). The most obvious sign of this will be that one photo will be clear and sharp wile another copy of it will be very blurry and pixelated. And in your photo's info the resolution will be significantly different.we a
If can narrow that down we can work on a solution.
