D drive is missing in Windows 7

My sister told me she could not find the D drive in her laptop any more. I felt strange: how could it happen, since all other partitions of the hard drive were visible? So I asked her to restart the laptop, check disk errors. Unfortunately, nothing worked. Guided her to look at the computer management tool, the partition was still there but Windows 7 thought it was unallocated.

For the sake of the data in that partition, have to find out another way to find the D disk back. Lucky enough, I came across a free partition recovery tool: MiniTool Partition Recovery. Following the tutorial on the website, it is easy to retrieve the missing partition. If you only have one partition missing or your lost partitions are continuous, the Quick Scan mode should work like a charm.