Restore Whatsapp chat and data I recently flashed my Xperia Z2, before flashing I took a backup of the Internal Memory of the phone, having an impression that the whatsapp data would be automatically restored. But after the flashing process completed and I installed Whatsapp again, I see no previous messages or data.

Does anyone have any idea on this.

Any help would be greatly appreciated.
Check the app you used to backup your internal memory. There should be a restore button in there that will restore the folders back to their original locations. You may have accidently backed up your apps instead of your settings/folders. If you did, then your data is sadly permanently gone. There may also be a setting in the app that lets you choose internal or external storage. I don't use Whatsapp so I don't know if there is, but if you do see the option under the settings, you may just need to switch it from one location to another so it can see the folder you backed up. If you could provide a little more data on how you performed the backup (what app you used, etc.) it would help in troubleshooting the issue further.