Some users, myself included, had noticed after the 3.3 upgrade that metadata searches weren’t completely reliable. For example, I had a project of 461 images all starting with the same name, yet a search for that name was only returning about 50 of the photos. Similarly, searches for “Canon” in EXIF > Camera Make were turning up nothing, even though they were all Canon files.
I repaired the database, but that didn’t fix it. I put off doing a full rebuild of the database but finally kicked that off last night, and I’m happy to report that all metadata searches are now working as expected.
So, if you are having any issues searching, try a full database rebuild. You should backup before doing this, by the way.
If you aren’t sure how this is done, check the ApertureExpert FAQ, and look for the entry “How do I repair or rebuild my Aperture library or permissions?”. If you haven’t been in the FAQ before, poke around… there’s a ton of great info in there.