The capacity shown might shrink or extend, but it will become inaccessible in your System. Physical damage to your USB Drive might result in a change in its capacity. Thus, when you divide your USB drive into multiple partitions, Windows fail to recognize more than one partition, resulting in your USB Drive not showing full capacity. Your USB Drives and other such external drives are meant to have a single partition. Formatting your Drive with incorrect methods or configuring it in the wrong way can lead to your Drive becoming inaccessible for the most part. Most of the time such issues occur due to faulty formatting of your USB Drive. Let's have a look at the various reasons causing your USB Drive to not show full capacity in Windows: Why My USB Drive is Not Showing Full Capacity in Windows? How to Recover Lost Files from USB after Restoring it to Full Capacity?.How to Restore USB Drive to Full Capacity in Windows 10/8/7?.Why My USB Drive Is Not Showing Full Capacity in Windows?.