I have successfully downgraded my iPhoto '11 library to '09, but it'll cost you $19.95 for *iPhoto Library Manager* (aka '
iLM') (
http://www.fatcatsoftware.com/iplm/). Please note: I'm not affiliated with the programmer, just a happy user.
• remove iPhoto.app ('11) from Applications
• install iPhoto from iLife '09 DVD
• install all updates via Software Update
• double-click iPhoto.app with "Option" key held until panel appears ⚠
-> you will be asked which library you want to use
• Create a new library, just to make sure that iPhoto starts without trying to read the '11 library
• Start iPhoto Library Manager
-> it will find all iPhoto Libraries on your Mac, if not, use "Add Library"
• Select the '11 library to be downgraded
• Choose "Rebuild Library" from File menu
• Choose place where the downgraded library should be saved
-> iPhoto will quit, starts with new library and imports.
This may take some time, of course. Unfortunately I sometimes got panels from iPhoto asking how to handle duplicates. iPhoto Library Manager will hang until you answer this question.
Nevertheless, after some hours I got 20665 pictures imported, all faces regenerated and everything as before, just back in '09.
At "http://www.fatcatsoftware.com/iplm/Help/print/index.html" you find the manual of iLM, where downgrading is briefly described as well.
Have good luck, but *please make sure that you have a backup of the '11 library*! It looks like the '11 library is NOT touched during this process, but who knows that for sure.
BTW: you can also use iLM to merge iPhoto libraries and much more. Nice app and up-to-date.
Update: please note that iPhoto of iLife '09 has version number "8", while iLife '11 contains iPhoto version "9". Little bit confusing, is'nt it?
Message was edited by: Robert Fischer, added version numbers of iPhoto.app in iLife '09 and '11.