I noticed this issue on my new Android phone, so I thought I’d share the fix for anyone else who might experience it.
When trying to Launch WhatsApp for the first time, it got stuck on the ‘looking for backups’ screen.
No amount of force closing or re-opening would get past this screen.
Well it turns out the issue is related to the app not having permission to your contacts.
So head into Settings -> Applications –> WhatsApp
Click the Permissions button
Turn on permission for contacts.
Now go and re-open the App and it should get past that screen and work.
Have fun !