I used the Lightroom plugin for migrating my photos from a managed library in Aperture to Lightroom. (Obviously I use a Mac.) The process monopolized my computer for a couple of days, and at the end, less than half of my photos had been transferred. Of the ones that had transferred, many had entirely lost their dates; others had only come into Lightroom as miniatures, usually without keywords. Some had had their dates altered and had been placed in wrongly-dated folders. I am now stuck going through my Aperture library one photo at a time to compare it to my Lightroom Masters, to see which ones are missing or messed up, marking photos in Aperture for export, exporting them a batch at a time, and then importing them into Lightroom. This is tedious, time-consuming, and frustrating.
What went wrong, and do you have any suggestions for how to proceed from here?