When I've checked "don't ask me again" in iPhoto, how can I undo it?

Delete the iPhoto preference file as follows

:

1 - delete the iPhoto preference file, com.apple.iPhoto.plist, that resides in your

User/Home/Library/ Preferences folder.

NOTE: If you're moved your library from its default location in your Home/Pictures folder you will have to point iPhoto to its new location when you next open iPhoto by holding down the Option key when launching iPhoto. You'll also have to reset the iPhoto's various preferences.

NOTE 2: In Lion and Mountain Lion the Library folder is now invisible. To make it permanently visible enter the following in the Terminal application window: chflags nohidden ~/Library and hit the Enter button - 10.7: Un-hide the User Library folder.

OT

Wow, this solution is pretty drastic. It's like saying you need to wipe your Mac to remove one program.

There is only one setting in the preferences file that needs to be removed. You can do this easily by:

Opening the iPhoto prefs file Old Toad refers to, then searching for 'DontAskAboutDeleteConfirmation' and changing its value from "YES" to "NO"

You can do this easily with one line from Terminal.app:

defaults write com.apple.iPhoto DontAskAboutDeleteConfirmation NO

I wonder why you choose to bring up a 7 months old solved thread where the posted is totally satisfied with the result

AS to your analogy of wiping your Mac clean to remove one program Not at all - it is like saying you need to set your preferences back to default and does not involve restoring any data or reinstalling all programs like you suggest

unfortunately few users are familiar with or comfortable with Terminal

Old Toad's method is a simple, effective and easily understandable and easily implemented way to resolve this and other issues with iPhoto

LN