I spotted this in my Software Update. Here's the scoop directly from Apple...
Aperture 1.5.3 addresses issues related to overall reliability and performance in a number of areas, including:
- Generation of thumbnails for adjusted images
- Entering and exiting Full Screen mode
- Working with large sets of keywords in the Keywords HUD
- Restoring from a vault
Among the specific issues that have been addressed:
- Previews now update properly when images are sent to an external editor.
- Leaf Aptus 22 and Aptus 75 images are now imported with the correct orientation.
- When folders are imported as projects, the folder structure is now correctly preserved when identically named subfolders are included in the hierarchy.
- Reconnecting referenced images that have been externally edited now works more reliably.
- Setting the ColorSync profile in the Aperture Print dialog now correctly suppresses color management settings in the Mac OS X Print dialog.