Generation of previews is still a very significant problem

Question

An old problem surfaced again yesterday, after several years of stability.
I decided to upgrade my previews in preparation for a move to a new iPad.  My reading says that, with the retina screen, the new iPad is capable of handling larger image files and showing much more detail than previous machines.
I have had much of my Aperture Library on my iPhone for well over a year and I liked this functionality.
So I set my preference for Preview quality higher and selected all my photos (around 22000) and started an "Update Previews".  Three or four times, the process crashed and I restarted it.  Then there was a crash that could not be handled.  Each time I rebooted Aperture, it crashed before I could do anything about it.
So I did all three recovery procedures.  Holding down Command-Option on reboot, I repaired permissions, repaired the database and then rebuilt the database.  This let me reboot successfully, but once the Update Preview recommenced automatically, Aperture crashed again.
My reading says that there was a corrupted file somewhere.  But there's no way to find it without trying Update Preview on one or two or a few image files at a time—a process which could take days or weeks with a big library.
So I wiped my disk clean and copied over one of my back-up libraries and gave up on the Update Preview.  Presumably, my back-up library has the corrupt file in it and I wasn't about to lose all Aperture functionality again.  Fortunately, I maintain a number of Vaults and other Library back-ups (created outside Aperture), so I can recover when my default Library gets into a state like yesterday.
The bottom line is this—there appears to be no way to easily root out a single corrupted file.  When you try to generate a Preview of a corrupted image file, Aperture will crash, and sometimes this is fatal and you have to simply replace the library you are using.  So there's a crying need for an effective method of finding and correcting a single corrupted file, AND/OR the software should report a corrupted file, but carry on with the generation of previews for the thousands of good files.
I've decided to avoid this problem in the future by changing my work method.  I can do without the previews.  I've turned off the Maintain Previews for this Project, for all my projects.  I will select a few of my best images and will create high-end previews of them for my iPad and that will satisfy my needs.

Answer 1

My reading says that there was a corrupted file somewhere.  But there's no way to find it without trying Update Preview on one or two or a few image files at a time—a process which could take days or weeks with a big library.
Yes, that procedure would be terribly slow on a large library: But you could search more efficiently by a "divide and conquer" method:
Back up your library.
Divide the set of images in your library in two albums of equal size; album A1 and A2.
Try to build the Previews for all images in Album A1 at once.
If that succeeds, you know that does A1 not contain the corrupted image - you'll have to search A2 next.
But if it crashes again, the corrupted image is in A1 and not A2.
Depending on the first result now build two albums B1 and B2 from the images in either A1 or A2 (depending on the result of step 1).
Then divide again, and again, and again, until the album is so small that you can spot the broken image.
Using this subdivision strategy you could scan 100000 images in only 16 steps
So there's a crying need for an effective method of finding and correcting a single corrupted file, AND/OR the software should report a corrupted file, but carry on with the generation of previews for the thousands of good files.
d’accord!    Have you sent feedback to Apple? http://www.apple.com/feedback/aperture.html
Regards
Léonie