Question HDD space had shrink after reboot during fragmentation

[AriX17]

HDD - IDE Samsung SP0411N. Nominally - 40 Gb, really - 37.2 Gb.
During the fragmentation PC suddenly rebooted. After it, HDD space shrinked to 31.5 GB.
Firstly I thought that the rest Gb's become unallocated space, Disc Manager say it's not (
Hot to restore missing Gb's ?

 

[R_1]

try re-partitioning the drive.
worst case scenario you replace it with a 64Gb thumb drive.
40GB were the standard sized hard drive 20 years ago. age happens