Please provide a lot more information.
Describe your hardware with detailed specs - CPU, GPU, RAM etc.
Describe your software: what OS? After Effects version? Third party plugins?
Describe your project - how complex is it? What effects does it use?
It looks like you might be using a template project, like a Videohive animation. Please let us know the details if that's the case.
Thanks RameezKhan This seems to have worked :
Correct Answer by RameezKhan on Jun 23, 2017 4:56 AM
Rename the After Effects folder to OLD_After Effects in the following locations:
Location 1: When in Finder, click on Go > Go to Folder > ~/Library/Application Support/Adobe
Location 2: Go > Go to Folder > ~/Library/Preferences/Adobe
Location 3: Documents > Adobe
NOTE: This will reset AE preferences and customization
Hope this helps.