If the size of a disk (USB pen drive or another external device) is displayed as several kilobytes or megabytes, it may signal certain memory issues. Such error often appears because of trouble with the disk’s microcontroller. You can try the following to solve this problem: Using specialized utilities provided by the manufacturer. Many SSD and flash drive manufacturers offer special utilities to recover and repair their devices. For example, Transcend, Kingston, SanDisk and others have their own software for diagnostics and repairs. Formatting the drive: If the data doesn’t matter or you have already saved it, try formatting the drive with the Command Prompt (diskpart). Using specialized software to perform low-level formatting. For example, HDD Low Level Format Tool lets you perform low-level drive formatting which can help you solve microcontroller issues.