One thing you can try is to reset the adjustment prefs.
- Select the following from the Go/Go To Folder option from the Finder menu bar.
- type ~/Library/Application Support/Aperture
- Then copy the Aperture folder to your desktop so you can get back to it if you need.
- Then delete the Aperture folder from within the Library/Application Support folder.
You can also try resetting the Aperture.plist.
- Select the following from the Go/Go To Folder option from the Finder menu bar.
- type ~/Library/Preferences/ and locate the com.apple.Aperture.plist
- Then copy the com.apple.Aperture.plist to your desktop so you can get back to it if you need.
- Then delete the com.apple.Aperture.plist from the Library/Preferences folder.
Log out of the system and then log back into the system.