Where did 30GB go from the disk?

Question

Iron

One not very good morning, I discovered that 30GB had gone somewhere from the D drive.
I recorded the acronis, booted from the USB flash drive and found two partitions as it should be, but even there you can’t see where the GB went in the sum of the two partitions was 465GB (500GB was the size of the hard one).
Tell me where to go, can check for broken sectors.

Answer 1

The manufacturer considers that 1 gigabyte is 1000 megabytes, and Acronis that it is 1024 megabytes... and so on.
This is how it turns out

500 * 1000 * 1000 * 1000 / 1024 / 1024 / 1024 = 465

Units of measurement of media capacity and volume of information