This question already has an answer here:
Yesterday I had two NTFS partitions on my drive. One on which Windows 7 was installed (C Drive) and the other contained my data (D Drive).
During Ubuntu installation I choose to install Ubuntu and erase my existing OS. When Ubuntu installed, I was shocked to see no partition. All my data was gone. I must have done something wrong in selecting my option during installation.
Is there any way I can recover my D Drive?