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USB Data Recovery Case Study: A Cautionary Tale

USB Device Not Recognized

The last USB device you connected to this computer malfunctioned, and Windows does not recognize it.

The client in this data recovery case had a failed USB flash drive on their hands. Whenever they plugged their Verbatim flash drive into their computer’s USB port, the computer would inform them that “One of the USB devices attached to your computer has malfunctioned, and Windows does not recognize it.” The client had been using their flash drive to store critical documents, and now that the flash drive had stopped working, their documents were gone. The client came to us in the hopes that our technicians’ USB data recovery expertise could reunite them with their lost files.

USB Device Not Recognized

The last USB device you connected to this computer malfunctioned, and Windows does not recognize it.


USB Data Recovery Case Study: A Cautionary Tale
Drive Model: Verbatim NG0863712010642DML
Drive Capacity: 8 GB
Operating System: FAT32
Situation: After improperly ejecting the flash drive, the user’s computer could no longer recognize the USB device
Type of Data Recovered: Documents
Binary Read: 99.9%
Gillware Data Recovery Case Rating: 10


The client had received the error message from Windows after too hastily removing their USB flash drive from their PC. They’d probably gotten away with this dozens of times before. But this time their bad habits had finally caught up with them. Now they had a failed USB thumb drive on their hands filled with important—yet inaccessible—data.

USB Data Recovery: USB Not Recognized

When you too hastily eject your USB flash drive and your PC won’t recognize it anymore, which part of the drive has failed?

Mechanically, your flash drive is still fine. The USB plug itself still works, the PCB hasn’t shorted out, and the controller chip and flash memory chip are still healthy. What has failed is the logical structure of the flash drive.

When you access a data storage device, be it an internal or external hard drive or SSD or a USB flash drive, your computer follows a chain of machine logic to reach the physical location of your data. If a part of that logical chain breaks down, your computer becomes a blind man in a dark room trying to find a black cat.

Safely Remove Hardware and Eject MediaRemoving a USB flash drive without properly ejecting it from your computer first can break one or more links in the logical chain. Your computer might be in the middle of a read or write operation, even if you don’t know it. If you’d tried to eject the device properly, your computer would say, “Hey, hold on! I’m not done with that!” and you’d know to wait and then try again. Interrupting the computer can cause data corruption that breaks the device’s logical chain. It’s a bit like yanking a sandwich out of someone’s hands in mid-bite.

When you unsafely eject a removable storage device, the most at-risk link in this logical chain is the partition table. This link in the chain points to the locations of the device’s partition superblocks, which go on to further describe the setup of the drive’s filesystem and its partitions. Most external devices, especially USB flash drives, only have a single partition. Improperly ejecting your flash drive doesn’t always corrupt the partition table. But when it does, it makes your device appear blank. Without that partition table, your computer doesn’t know how to read any of the data you’ve put on the drive.

USB Data Recovery Results: Remember to Safely Remove Hardware and Eject Media

USB data recovery

PCs aren’t the only computers that require you to safely eject media. This error message comes from Mac OS X: “The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off. To eject a disk, select it in the Finder and choose File > Eject. The next time you connect the disk, Mac OS X will attempt to repair any damage to the information on the disk.”

Our USB data recovery experts managed to successfully create a near-perfect disk image of the client’s failed flash drive. Some of the logical corruption which had caused the device to fail impeded our technicians’ work, but further logical analysis by our data recovery technicians revealed that the FAT32 directory structures of the flash drive, as well as all of the files on the drive, were fully intact. Our technicians rated this USB data recovery case a 10 on our ten-point scale for a perfect data recovery outcome.

When you need to eject an external data storage device, such as an external hard drive or a USB flash drive, there is a proper protocol you should follow. You need to tell your computer to “eject” the device before you unplug it. By telling the computer to eject the device, the computer makes sure it’s not still trying to use it first. Then it gives you the go-ahead to remove the device safely. If your computer is still using the device, it makes sure to let you know. Sometimes the user might grow impatient and proceed to simply yank the USB plug out of their computer.

It might not seem like it, but this is a risky move to make. This exact action is what caused the client’s USB flash drive to stop working properly. While it might not seem like it, and while you might get away with doing it dozens of times, improperly ejecting your thumb drive always carries a significant risk of causing the device to malfunction. If you have valuable data living on your external device, it’s always in your best interest to follow the rules whenever possible. Otherwise, the next time you unplug your flash drive from your computer could very well be your last.

Will Ascenzo
Will Ascenzo
Will is the lead blogger, copywriter, and copy editor for Gillware Data Recovery and Forensics, and a staunch advocate against the abuse of innocent semicolons.