Upgrading to the latest version of iPhoto has caused a few users some problems where the program would hang during the library conversion, and in some rarer cases has resulted in lost photos. Apple has addressed this problem in an update to iPhoto (version 9.0.1) that was released on Friday.
The update is a 33.87MB download that is available at the iPhoto 9.0.1 download webpage. While this should be available through Software Update, if you have not yet installed iPhoto '11 then first download this update, and apply it immediately after installing the new version. Do this before launching the program for the first time, to ensure you avoid launching version 9.0.0.
As always, the best safeguard against data loss is to keep a backup of your library, so be sure to fully back up your system before installing the new version of iPhoto, even if you have installed the latest update.
Apple has a knowledgeable article with information on this latest version and the problems it addresses. Before upgrading be sure you read it so you are aware of what to expect when upgrading to iPhoto '11. Apple specifically warns of the following conditions:
- Upgrading large libraries may take a long time--over an hour
- Upgrading after force-quitting a previous attempt may result in data loss
- If you have force-quit a prior upgrade, be sure you have iPhoto 9.0.1 installed before trying again