Why the computer does not see a USB flash drive or external hard drive and what to do about it

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Common causes and simplest solutions to the problem.

Why the computer does not see the USB device

Usually, the suspects in this case are software malfunctions, incorrect operating system settings, outdated drivers, malfunctions of the computer's USB ports, adapters or the drives themselves.

Depending on the reasons, in each case the problem manifests itself in a different way. It happens that the computer does not react at all to a USB flash drive or hard drive. In other situations, the sound of connecting a new device is heard, but the drive icon does not appear in the explorer. And sometimes the computer just freezes right after contact with the USB device.

What to do if a Windows computer does not see a USB flash drive or external hard drive

First you need to decide what exactly the problem arises: with a computer, an adapter (if the connection is via a cable) or a drive.

1. Try connecting your USB device through different ports. If it works fine there, then there is a problem with the specific USB port. We'll have to take the computer for repair.
2. If you are using a cable, try replacing it with a spare. Perhaps this will fix the problem.
3. If you are connecting the drive via a USB hub, disconnect the hub and plug the device directly into the port. The hub may be defective or it may not have enough power to power the drive.
4. If unsuccessful, check if the drive opens on other computers. Is the other device okay? So the problem is in your system. And we will try to solve it.

If you managed to open the contents of a disk or flash drive on another PC, it doesn't hurt to make a backup - just in case.

If the device works on another PC or you have no way to check it

Connect a hard drive or flash drive to your computer and follow these steps in order. If the first does not help, move on to the next and so on.

1. Check the drive settings in the Disk Management menu. Right-click the Start menu and select Disk Management. Or open a command prompt window (Windows key + R), then enter diskmgmt.msc in it and press Enter.

If you see a disk without a volume label in the Disk Management menu, this may be the cause of the problem. Right-click on it and assign a letter to it using the appropriate option in the context menu. You can find out that you have chosen exactly the disk you need by its size.

Read all system warnings carefully to avoid accidentally formatting the drive or altering the data stored on it.

After that, the disk should be visible in the "Explorer".

2. Check the disk layout. Make sure the partition is properly partitioned on the device. To do this, find it in Disk Management. If the bar denoting space on the disk is not blue, but black and is marked as "Not allocated", then you need to create a partition on it.

Right-click the black bar and select Create Simple Volume → Next → Next → Next. In the "Format this volume as follows" section, select NTFS if you have a large disk, or FAT32 for a flash drive. Click Next → Finish.

This problem often occurs with newly purchased devices that have not been formatted at the factory. This method should be used only if you are sure that there is nothing of value on the disk.

3. Check the file system of the disk. Maybe the drive you're trying to connect to your Windows computer has been formatted in the past on systems like macOS or Linux. Then it is quite possible that the file system on it is not NTFS or FAT32, as in Windows, but some kind of ext4 or APFS. Windows does not know how to read them and, when connected, prompts you to format the disk. Naturally, then you will lose its contents.

Connect the disk to the computer on which you formatted it and copy the data from there. Then reformat the drive to the less exotic NTFS or FAT32 if it's a small flash drive.

4. Check your hardware settings in Device Manager. To open it, right-click the Start menu and select Device Manager. Or type devmgmt.msc at the command prompt (Windows + R) and press Enter.

Pay attention to the section "Disk drives". If you see a non-working device (with a question mark or an exclamation mark) there (or in any other section, for that matter), an update might help.

Right click on this device and click "Delete". In the top menu, click Action → Update Hardware Configuration.

5. Update the driver in Device Manager. Until you close the Device Manager window, right-click your drive and click Update Driver. Sometimes it helps.

6. Install the latest updates for Windows. Without them, the operating system may lack the necessary fixes to work with modern USB drives. This is especially true for old and unsupported Windows XP.

If the other PC does not see the drive either, or all of the above tips did not help

In this case, the problem is most likely in the drive itself.

If you have a flash drive, not a hard drive, you can use special utilities to fix software errors. Such software can usually be found on the manufacturer's website. For example, JetFlash Online Recovery is for Transcend drives. And USB Flash Drive Online Recovery is for ADATA flash drives. Please note, however, that these utilities will erase all data during the recovery process.

If none of the above helped, then it is probably a physical malfunction of the hard drive or flash drive. Then it is better to show the device to a specialist or return it to the store under warranty.

What to do if Mac does not see a USB flash drive or external hard drive

On Apple computers, the verification procedure is somewhat different, but it follows approximately the same algorithm. We will assume that you have already tried restarting your computer, disconnecting and connecting a USB flash drive, and also made sure that the connection is reliable. If this does not help, you need to do the following.

1. Check the drive in "Disk Utility" … Open the built-in tool for working with disks ("Programs" → "Utilities" → "Disk Utility") and check if the problematic flash drive is displayed there. If the drive is still visible, try reformatting it by clicking the "Erase" button and reconnecting it. Keep in mind that all data from the flash drive will be deleted in this case.

The First Aid tool can also help. Select the drive you want and click the stethoscope button on the panel, then click Run → Continue.

2. Reset NVRAM and SMC. This sometimes helps with hardware problems. Instructions on how to reset are located here.

3. Make sure the disk is compatible with macOS … MacOS has certain difficulties in recognizing disks formatted in Windows in NTFS. She can read them, but not change them. To teach a Mac to work with such a file system, you have to fork out for Microsoft NTFS for Mac from Paragon Software. Or copy data from disk and format it to FAT32.

4. Check the drive in "System Information" … A dedicated Mac diagnostic program provides detailed information about all the software and hardware components of your computer, including USB devices. Open the Apple menu, then hold down the Option key and click System Information and navigate to the USB section in the menu that appears.

If the flash drive is there, then the problem lies in the software and you can try to restore the disk by referring to the manufacturer's recommendations. If there is no information about the flash drive, then the matter is in a physical malfunction, and you should contact a store or service center if the repair makes sense.

The text of the article was last updated on February 12, 2021.