A fresh install of Win10 1903 and 1909 contains 7 GB of "Reserved Storage". This 7 GB is included in the Used space number of Disk Management. However, these boot disks, BootIt, GParted, Linux, Macrium, AOMEI and ACTIVE@ Disk Image do not see the 7 GB included in the Used space. They see 7 GB more Free space than Win10 sees. So these apps will let you resize the Windows partition to have less than 7 GB of Free Space. If you do this, Win10 will no longer boot and it can't be fixed. Resizing back to the original size doesn't help. I'm advised it's a Win10 bug.