Why is the labeled capacity of the Xiaomi Dual-interface Flash Drive 128GB not equal to the available capacity?

The actual capacity is not equal to the labeled capacity. Flash or hard disk devices are calculated in base 1000, meaning 1KB = 1000Bytes, 1GB = 1000M, whereas operating systems calculate in base 1024, meaning 1KB = 1024Bytes, 1GB = 1024M. Therefore, there will be a certain difference between the labeled capacity and the actual capacity of the product in the operating system, and in different operating systems, system files will also occupy a small amount of space, which is a normal phenomenon.
Note:
If the drive has been partitioned or if there is a portion of its capacity that appears unallocated in disk management, this issue can be resolved by formatting. In cases where formatting is not possible, deletion and recreation of partitions will be necessary.