Apple has released iPhoto 4.0.1, an important bug fix update to the company’s photo management program. Although Apple’s release notes are, as usual, short on specifics, iPhoto 4.0.1 features improved performance, better thumbnail rendering, and numerous bug fixes that Apple claims improve stability. I’ve been able to confirm that the Trash album now reports its size, the Sepia command in the image editing window’s contextual menu is no longer disabled, and modifying film rolls no longer changes your overall sort order. Other bugs remain, such as the one that forgets to add "copy" to the name of edited photos you duplicate. The only new feature I found while checking the final draft of my iPhoto 4 Visual QuickStart Guide is that slideshows now play on the monitor containing the iPhoto window, assuming you have multiple monitors.
The improved thumbnail rendering requires that iPhoto upgrade your thumbnails; it’s a slow process that took an hour for my 6,100 photos. Short of that, iPhoto 4.0.1 has been more stable in my testing, although some users on Apple’s discussion boards have reported problems with launching the application and with losing transitions in slideshows. The problems appear to be related to permissions within the iPhoto application bundle, the usual troubleshooting steps may help (repair permissions using Disk Utility, delete the com.apple.iphoto.plist file from your ~/Library/Preferences folder, reinstall iPhoto, and run DiskWarrior to fix directory problems). If those fail, try copying the iPhoto application to a network volume or external hard disk with Ignore Permissions On This Volume checked; then copy it back to your hard disk. Alternatively, try this user-posted fix.
iPhoto 4.0.1 is a 4 MB download via Software Update; it’s also available for independent download.