If you shrink a logical partition, you get free space, while a primary partition gets the unallocated space. Unallocated space and free space that you see in disk management are both unusable storage space. In any case, you need to be more careful and attentive to your information storage devices. In addition, improper formatting, accidental deletion of one of the partitions or corrupted file systems can cause a USB flash drive to run out of allocated space. As a result, the problem of unassigned USB sticks is more common. Many users have encountered the following problem: a used storage device, such as a hard disk, USB stick, SD card or pen, is missing in the file explorer and marked as “unallocated” in disk management, which is quite confusing and annoying.Ī USB stick is a removable disk and is therefore more susceptible to viruses and worms than hard drives. Have you ever experienced the following problem: your SD card or USB stick suddenly appears unassigned or even stops working on your PC? After that, you can neither access the data nor store new data on it. Update: Stop getting error messages and slow down your system with our optimization tool. Fix Hard Drive Unallocated Windows 10 with CMD and Disk Management.Repair Unallocated USB Hard Drives with Disk Management.