There is an uninstaller, but as the developer is not trustworthy, you shouldn't rely on it. I suggest the tedious procedure below to disable Genieo.
Quit the Genieo application, if it's running. Triple-click anywhere in the line below on this page to select it:
Services ▹ Reveal in Finder (or just Reveal)
from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator password.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.
Repeat with each of these lines:
/Applications/Uninstall Genieo.app
/Library/Frameworks/GenieoExtra.framework
/Library/LaunchAgents/com.genieo.engine.plist
/Library/LaunchAgents/com.genieoinnovation.macextension.plist
/Library/LaunchDaemons/com.genieoinnovation.macextension.client.plist
/Library/PrivilegedHelperTools/com.genieoinnovation.macextension.client
/usr/lib/libgenkit.dylib
/usr/lib/libimckit.dylib
/usr/lib/libimckitsa.dylib
Note: Some of these items may be absent, in which case you'll get a message that the file doesn't exist.
The following configuration file may be either created or modified by the Genieo installer:
/etc/launchd.conf
The file is unlikely to be used by anything but Genieo or something equally undesirable. Unless you know you need it, delete it in the same way as above, if it exists. Otherwise, edit it to remove the line that begins as follows:
setenv DYLD_INSERT_LIBRARIES
The above is not a file, but a line inside a file.
Reboot. Your web browsers should now function normally, and you should be able to reset the home page and search engine. If not, stop here and post your results.
From the Safari menu bar, select
Safari ▹ Preferences ▹ Extensions
Uninstall any extensions you don't know you need, including one called "Spigot" if it's present. If in doubt, uninstall all extensions. Do the equivalent for the Firefox and Chrome browsers, if you use either of those.
The Genieo installer may also install the "Silverlight" web plugin from Microsoft. If you have no use for that plugin, you should remove it according to Microsoft's instructions. Don't remove it if you subscribe to "Netflix."
This procedure may leave a few files behind, but it should deactivate Genieo. Make sure you don't repeat the mistake that led you to install it. Chances are you got it from one of the Internet's open sewers such as "Softonic" or "CNET Download." Never visit either of those sites again.
