Q: effect preview in aperture 3

how to enable effect preview in aperture 3

Adjustments (Effects) are applied instantly in Aperture, so you see the result immediately. You can toggle the effect on and off by clicking the "enable" button to the left of the adjustment brick in the Adjustent panel to compare the image with or without the effect enabled.

What effects are you using?  Brushes?  Then check the setting for the brush range: Make sure the Brush Range is set to "Al"l and not restricted to certain tones.

You can check by enabling "Color Overlay", if the brush is effective at all.

Are you not seeing a fly-out preview when you hover on the name of a saved Effect in the Effects drop-down on the Adjustments Inspector?

You trouble-shoot this by seeing if the same failure is present in a new Library, and in a new Library created under a different User Account.

You can also skip straight to deleting your user preferences, as detailed on the Apple Aperture trouble-shooting page.  This almost always fixes UI problems, which it seems is what you have.

Let us know what you do or find out.

Perekirill,

did you do as Kirby recommended and delete the User Preferences?

You can also skip straight to deleting your user preferences, as detailed on the Apple Aperture trouble-shooting page. 

And did you logg off?  After removing the Preferences files it is essential to log off and on again, or to restart the computer, before you launch Aperture again.  Otherwise it may not take effect.

These files and folders need removing:

~/Library/Preferences/com.apple.Aperture.plist

~/Library/Containers/com.apple.Aperture

Did you uninstall an incompatible Aperture version? I am a bit puzzled by the "Ghostbuster" Aperture icon in your Trash.

What is your MacOS X version?

If you reinstalled Aperture from your installation disk, you need to update it to a version that is compatible with your current Mac OS X version. Download and run an updater from the Support Page:

http://support.apple.com/downloads/#Aperture

If your Presets are gone, you have not deleted the Aperture Preferences, but your Presets from ~/Library/Application Support/Aperture/  folder in your uer library or your system library.  If you still have the folders "Application Support/Aperture" put them back where you removed them from.  If they are in the Trash, you can ctrl-click them and use "Put Back".

What version of Aperture is it, that is currently running?  That you are using for the screenshots?

Look at the "About" panel -          Aperture menu > About Aperture

If you are using Aperture 3.5.1, you should be able to reinstall it from the AppStore. Move Aperture to the Trash (don't empty the Trash), then sign into the AppSTore with your AppleID and go to the "Purchased" tab. Click "Install".