How to resolve unable to start atg wizard(Plug-in "atg.project" was unable to instantiate class "atg.eclipse.project.wizard.ProjectWizard".)

How to resolve:

When we are creating new atg project will get below error some times..

The selected wizard could not be started.
Plug-in "atg.project" was unable to instantiate class "atg.eclipse.project.wizard.ProjectWizard".
atg/applauncher/AppLauncherException

Step1 : In Eclipse got Window-->Preferences -->ATG Preferences

In ATG Prefeernces please select/browse the exact path of ATG Root Directory

Step 2.Select the Perspective as ATG 

Step 3: Copy the ATGUpdateSite.jar file from D:\project\ATG\ATG11.1\Eclipse\ATGUpdateSite.jar

to D:\project\Eclipse\plugins Folder

Note : Restart your eclipse if its already opened.