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17 January 2019  Ashley S. Miller  Specialist of Customer Service Dept.
 

Summary
It is common that we may find that the connected USB flash drive not showing up, recognized or even can not access to data inside. We will go through all possible reasons and solve this problem step by step.



There are lots of reasons which can lead to the USB flash drives does not show up in Windows after connected to PC. These reasons could be divided into 3 types:
Solution could be found on the Internet to solve the not showing up USB flash drives and USB devices. However, most of them lack of step by step guidance and users are hard to know which one is a suitable way to solve the problem they have met.
However, USB flash drive is important because it save lots important and private data for users. If we format the USB flash drive to regain its function, we will lost all important data inside.
Here, we will analyze all possible problem we may meet when using the USB flash drive and provide related solution and detailed steps.

Situation 1: Receive that “You need to format the disk in drive X: before you can use it.” and can not access to data inside

Situation Analysis

This situation could be caused by the corrupted management information of file system in USB flash drive. Generally, the following 2 behaviors could damage the management information of files system:
  1. User does not remove the USB flash drive with the eject function in Windows after using the USB flash drive.
  2. Save plenty of files to the USB flash drive in a short time (Generally in Windows XP).
Besides, there is a third reason could cause this situation. That is the file system of the USB flash drive is not supported by Windows. Such as HFS in Mac OS and ext in Linux.
eject USB flash drive

Solution

Please solve this problem with steps below:

Step 1: Confirm the file system of the USB flash drive.

If you use the USB flash drive in Windows PC or Android devices (both system use FAT file system), please go to step 2.

If you use the USB flash drive in Mac OS or Linux, please go to step 4.

Step 2: Recover important data from USB flash drive with data recovery software.

If you do not want to recover data from the SD card, please skip this sector.
Here, we recommend data recovery software Photorec and Renee Undeleter.
Photorec is a freeware which can scan your disk and find some lost files. However, its interface is hard to understand.
select disk in photorec

- Select target disk in Photorec -

use photorec to recover deleted data from micro sd card

- Check scan result in Photorec -

The other data recovery software we recommend is Renee Undeleter. It can preview the scanned lost files before recovery when scanning process. Also, it can scan whole disk to find lost files. This can help users to confirm the quality of the recovered files.

Preparation: Download and install Renee Undeleter.

press to the download button

Step 1: Launch Renee Undeleter and select “Whole Partition Scan”.

select whole partition scan in renee undeleter

Step 2: When the software scan, we can preview the files in the scan result.

Although Renee Undeleter is a shareware, it has 20MB free recovery quota (Click here for more information). We recommend users can make use of this 20MB to ensure the recovery of important files.
preview before recovery

Step 3: Repair the SD card after data recovery

Method 1: Repair USB flash drive with Windows built-in chkdsk tool

Here we use the built-in free tool – Chkdsk to repair the USB flash drive. Chkdsk only supports FAT and NTFS format of Windows. If your USB flash drive is in other partition formats like HFS or ext (For Linux only), the only method is to format it.
Chkdsk will repair the file system and will directly abandon or overwrite some files or directly which is damaged seriously. So, data recovery will not work any more once users process the Chkdsk. So, please recover important data with data recovery software above before repairing the USB flash drive.

1. Press Win + S button and type “cmd” in the pop-up window. Right click “Command Prompt” and select “Run as administrator”.

run command prompt as administrator in start menu

2. Type “chkdsk X:/F”. Please modify the X to the drive letter of your USB flash drive. And /F means fix the USB flash drive.

type c to check the c disk

Method 2: Format USB flash drive with built-in Windows format tool

If Chkdsk notifies you that there are too many error information in USB flash drive and can not repair it, you need to format the SD card.
format SD card

Step 4: Get access to files inside the USB flash drive with other third party software.

If your USB flash drive was used in Mac OS, please install freeware HFSExplorer.
HFSExplorer
If your USB flash drive was used in Linux, please install freeware ext2explore.
ext2explore
Remember to click “Eject the USB disk” in Windows taskbar and remove the USB flash drive until Windows notifies your that the USB disk has been Removed successfully. Or file system of the USB flash drive will get corrupted and require to format the disk.
eject USB flash drive
If Windows fails to eject the USB flash drive, please shut down related software and then try again. Or you can shutdown the computer and then remove the USB flash drive.
fail to eject the usb devices
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Situation 2: Windows notifies that “USB Devices Not Recognized” after connect USB flash drive to PC

usb ports are not working

Situation Analysis

This problem could be caused by the insufficient power supply, incorrect connection or incorrect settings in BIOS. Here we can find the reason with exclusion method.

Solution

First, we could connect the USB flash drive to another computer. If same problem happens, the USB may have electrical problem and you need to connect the manufacture for repair.
If other computer can get access to data inside the USB flash drive, please connect the USB flash drive to computer via the USB ports in the back of the PC. It would be better if you connect to the USB 3.0 port. USB 3.0 port can provide about 1000mA power while general USB port only provide 500mA power.
usb port with flash sign
Please try the methods below if the USB flash drive is still not showing up or working:

Method 1: Restart PC and change the USB settings in BIOS

Step 1: Please refer to your manual for about how to enter BIOS of your PC. You could also refer to the passage here How to set your PC boot from USB/ CD device.
usb configuration
Step 2: Find “Integrated Peripherals” after entering BIOS and “Enable” the “USB Controller“ and “USB 2.0 Controller”.
Step 3: Save the settings and restart the computer.

Method 2: Uninstall related driver of USB ports and do not eject or remove the USB disk. Restart the PC

Step 1: Press Win + R button and type “devmgmt.msc” in the pop-up window. Click “OK”.
enter device management interface
Step 2: Please find all “USB Mass Storage Device” and “USB Root Hub” which has been marked with “?” sign in “Universal Serial Bus controllers”. And right click these devices and select “Uninstall” in the menu.
how to repair undetected micro sd card by uninstalling drivers
Step 3: Restart the computer without removing the USB flash drive.
All driver related to the USB drive will be reinstalled and set when computer restart.
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Situation 3: Computer can not recognize the correct capacity of the USB flash drive or require to connect the disk

Situation Analysis

This problem could be caused by the following 2 reasons:
  1. Clone the USB flash drive with smaller capacity to another one with larger capacity with clone software which does not support size extend. And the software make them with the same capacity.
  2. Some incorrect operations or the controller of USB flash drive which was influent by the magnetic materials like cell phone will mess up the control information of the USB flash drive. As a result, Windows can not recognized the USB flash drive as usual. Even you connect the USB flash drive to computer, it will ask you to connect the disk.
connect disk to pc

Solution

First, we can try to format the USB flash drive with Windows built-in format tool. This operation is the same in Windows 2K/XP/Vista/7/8/8.1/10.
Go to “Computer”. Right-click the USB flash drive and select “Format” in the menu. Click “Start” directly.。
foramt USB flash drive

Method 1: Low Level Format the USB flash drive

Generally, the capacity of the USB flash drive will return to normal. If we can not process the format, we need to reset the USB flash drive with some special tools.
What is Low Level Format?

Low level format will erase all file and data from the disk and factory reset the disk. There are lots of tools which can help users low level format the USB flash drive.

Option 1: Format Utility

If the USB flash drive you used is made by Kingston, please low level format the disk with Format Utility provided by Kingston. It works effectively but only for USB flash drive from Kingston.
Download link: http://www.drfreeware.org/kingston_format_utility.exe
Format Utility

Option 2: LLFtool – HDD Low Level Format Tool

Supports to low level format storage devices like hard disk, removable disk, USB disk. You can try this tool to fix the USB flash drive when the drive is not recognized.
Download link: http://www.drfreeware.org/HDDLLF.4.40.exe
LLFtool

Method 2: Mass-produce USB flash drive

Attention: This method only suitable for professionals. The USB flash drive will fail to work directly if the mass production fail.
Low level format will only reset the storage management information in the controller of the USB flash drive. If users need to reset more low layer information, mass production will be a good choice.

Step 1: Controller in the USB flash drive will be different even they are produced by same manufacturer. The first thing is to find out the brand of the controller. And then find the related mass production tool.

Here, we recommend ChipGenius.（Download link: http://www.drfreeware.org/ChipGenius_v4_18_0203.zip）

ChipGenius

Step 2: ChipGenius can help uses find out the manufacturer of the controller vendor in USB flash drive. Then please find the related production tool.

Here, we can find out that the manufacturer of controller vendor is Phison. You can find related mass production tool for Phison on the Internet and mass produce the USB flash drive.

Phison tool

Step 3: After mass produce, the USB flash drive can be used normally.

And if it does not work, please refer to Situation 4: Windows does not have any notification after connect the USB flash drive“.

Attention:
Please do not place the USB flash drive in any place with magnetic materials like cell phone.
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Situation 4: Windows does not have any notification after connect the USB flash drive

Situation Analysis

The process of finding out the real reason which causes this problem is complicated. It could be the problem of the USB flash drive or the connector of the PC or configurations.We should try to find the reason of the USB drive at first.

Solution

Preparation: Connect the USB flash drive to another computer. And please try to access data inside.
If you can access data in the USB flash drive, then this problem could be caused by the computer. To solve this problem, please go to “Step 2“.

If you can not access data in the USB flash drive after connecting to another PC, the USB flash drive could get some thing wrong. Here, please go to “Step 1“.

Step 1: Find out the reasons which caused the USB flash drive not showing up in the PC / PC can recognized the USB flash drive but does not have the drive letter.

1). Press “Win” + “R”. Type diskmgmt.msc in the pop up window and click “OK”.

enter diskmgmt.msc in run

2). If you can not find the USB flash drive was marked with RAW in the Disk Management, please go to “Step 2” directly.

raw drives are not available with chkdsk

3). If USB flash drive is marked with “RAW” and does not have drive letter, please format the USB flash drive directly.

If USB drive is marked with FAT/exFAT but do not have drive letter, please right click the disk and select “Allocate drive letter and path” in the menu. Follow the guidance and finish the settings.
format raw disk
perform quick format disk management
4). If the USB disk is marked with RAW. And we need to allocate the drive letter to it manually.

Right click the disk and select “Allocate drive letter and path” in the menu and follow the guidance.

change drive letter and path
change drive letter and path

Step 2: If we could not find any USB flash drive in the Disk Management, it could be caused by the USB disabled in Windows.

Generally, we can solve this problem with Registry Editor.
However, if the computer manager disable the use of removable storage devices with some third party software like Renee USB Block. If your computer has been disabled the use of removable storage device in this way, you need to apply for the permission.

1). Press “Win” + “R”. Type regedit in the pop up window and click “OK”.

enter regedit in run

2).  Find the value of “Start” through the following path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR

start value

3). If the value is 4, please double click “Start” and change it to be 3.

change the start value

4). Restart the PC and the USB flash drive will work normally.

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Situation 5: Require to enter the correct password to access data inside

Situation Analysis

Never encrypt the USB flash drive but require to enter the password when you want to access data inside? Then the USB flash drive could be encrypted maliciously by others.

Solution

Step 1: Check whether it’s virus which lead to the USB flash drive recognition failure.

Please install antivirus software like Avast, Norton, Kaspersky and scan the USB flash drive.
Generally, antivirus software will kill the virus and fix the recognition problem of the USB flash drive. However, some virus like Wannacry, CARDKEY will encrypt whole USB disk. As a result, the victim need to pay to the virus producer to unlock the USB flash drive.

If you encounter similar situation, please try to recover important data encrypted by Wannacry. If there is not any important files, please format the USB flash drive directly.

Step 2: Check whether the disk is encrypted by some system encrypted software.

Somebody may encrypt your USB flash drive maliciously with some USB disk encrypt software. If yes, please find and get the password.
Attention:

Please do not download or run files from un-trusted website. And do not handle USB flash drive with important data inside to someone you are not familiar with.

Situation 6: USB flash drive get hot after connect to PC for a while and Windows does not have any notification

Situation Analysis

If USB flash drive gets hot after connects to PC for a while, it could be caused by the short circuit. The USB flash drive may fall into water.

Solution

  • Blow the USB flash drive with hot mode in hair dryer for about 3-5 minutes. Place the USB flash drive with desiccant in sealable package. Seal the package and place for over 24 hours.
  • If the methods above do not work, please open the case of the USB flash drive and clean the inside carefully.
Attention:

Please do no place the USB flash drive in somewhere moist or dusty.

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