How to Fix USB Detected But Not Accessible Issue?

February 20, 2019

Have you ever met USB detected but not accessible issue on Windows 10/8/7? Or some other external storage device not accessible on your computer? This article will guide you to tackle with it easily.

Real user scenario

Guys! Please help, now I am suffering from a terrible situation where I plug my USB drive to computer, it is detected well, but cannot be opened. So I cannot access any data or files stored in the USB stick, totally a nightmare. All the data is quite important. Is there any fix for this USB detected but not accessible issue? Any help would be greatly appreciated!”- from a forum user

Are you also a victim of the above scenario? Or irritated with some other more terrible external storage media problems such as second hard drive not detected? Have no idea what to do under such situations? Just relax! Here, we will elaborately analyze why this happen and how to fix it to help you out!

What leads to USB flash drive detected but not accessible?

As for why USB flash drive, hard drives, memory cards, pen drives, memory stick or other external hard drives are not accessible in Windows 10/8/7, below are the main reasons you might need to take into consideration:

  • The USB drive is not partitioned at all. If the flash drive is a brand-new disk, and there is not any partition on it, then the system won’t recognize it. So it can be detected but not accessible.

  • The disk driver is outdated. In such case, you may find the USB drive recognized in Device Manager, but not in Disk management.

  • The USB does not have a drive letter. If a partition of the flash drive comes without a drive letter, then you cannot see it in Windows File Explorer.

  • The current file system is not compatible with Windows 10/8/7. If you are mainly running Windows PC, but the external hard drive is formatted to be Ext2/3/4, then it cannot be recognized by your computer.

Of course, there are some other causes for this issue including bad sectors on the disk, virus infection, or insufficient USB power supply.

How to fix USB drive not accessible in Windows 10/8/7?

USB flash drive detected but not accessible is a common problem particularly with a new USB stick. Due to this problem, whenever you connect it to computer, it gets detected easily, but it does not allow you to access files or data within it.

Fortunately, this problem can be solved by following solutions. You can try them one by one and check whether the issue can be solved or not.

General fix – Check USB Port

Before trying any other technical solutions, you should first check whether the USB port on your computer is fine or not. Try to insert your USB drive to another port of your PC, if it works well on another port, then there must be something wrong with the first port. If it still does not work, then connect the USB to another PC’s USB port, just to check if the USB stick itself is dead or your PC goes wrong. If it does not even show up in the Disk Management, then you might need to replace it with a new USB.

Technical fixes

If the drive itself, connect ports and computer are all fine, you might need to go for some technical fixes for USB detected but not accessible issue.

Fixes for: USB drive showing up in File Explorer but not accessible

It suggests that your device is recognized by your computer, but you cannot open any files or folder stored in it through File Explorer, then you can try the following solutions.

  • #1: reassign a drive letter to the USB

If the USB is lack of a proper drive letter, then there is a possibility that you cannot open it in File Explorer. In this case, you can reassign a new drive letter to it in Disk Management by following the below instruction.

1. Press “Windows” + “R” simultaneously, input “diskmgmt.msc” and hit “Enter” to open Disk Management.

2. Locate the USB disk partition, right click it and choose “Change Drive Letter and Path…”

3. In the pop-up window, click “Change” and assign a new drive letter to the partition.

  • #2: Run CHKDSK to ensure there is no bad sectors on the USB

If the USB flash drive is corrupted or there are some bad sectors on it, then you could not access it, either. However, you can try to run CHKDSK to fix such problems. Have no idea how to do it? Check below steps:

1. Click the Search box, type “cmd”, right click Command Prompt icon and select “Run as administrator”.

2. In the Command Prompt window, type "chkdsk d:/f", where the “d” stands for the drive letter of your USB partition.

If running such commands is never what you are good at, you can try AOMEI Partition Assistant, which offers a quite easy way to check bad sectors on hard drives.

  • #3: reformat the USB to a compatible file system

As mentioned above, if your USB is formatted to be Ext2/3/4 file system, then you will meet the message saying “You need to format the disk before you can use it” and “pen drive is not accessible and the volume doesn’t contain a recognized file system” whenever you try to open it in My computer. That’s because Ext file system is just compatible with Linux operating systems. So you need to reformat it to another more compatible file system, like FAT32.

Luckily, you can finish such task via the AOMEI Partition Assistant. Below is the instruction on how to format Ext2 to FAT32.

First, download the freeware, install and launch it. Click the USB device and hit on Format Partition option on the left side panel, then verify the FAT32 as the file system and follow the prompts to finish the formatting.

Select File System of 30GB USB

Note: since the formatting operation will destroy all the data on the partition, please copy partition to another hard drive in advance to ensure the data security.

Fixes for: USB detected but not showing up in File Explorer

If your device is detected by your computer, but it does not appear in File Explorer, then you cannot access any data within it. For such situation, the solutions below are worth your trying.

  • #1: Create partition on the USB drive

When there is not any partition existing on the drive, you can just see it in Disk Management shown as an unallocated space, plus it does not appear in My computer/This PC.

Generally, you can solve this issue by creating a new partition in Disk Management, but sometimes you might meet New Simple Volume greyed out error. But no need to worry, since you can also turn to AOMEI Partition Assistant.

Here is how to create a new partition using the software:

1. Run the disk manager software, right click the unallocated space or partition on USB drive and choose Create Partition from the menu.

Create Partition on Removable Drive

2. In the mini window, you can set the partition size, drive letter, file system according to your needs.

Resize New Partition on Removable

3. Back to the interface, click Apply to commit the pending operation.

Apply Create Partition on Removable

If your external storage device comes with a large size and you want to create several partitions on it instead of just one, you can upgrade this software to Pro Edition, since its Quick Partition feature allows you to create multiple partitions with only a few easy clicks.

  • #2: Update device driver for USB drive

This method works for the USB drive even not showing up in Disk Management. Below is how to update the device driver.

1.  Right-click on Start, click “Device Manager”.

2.  Expand Disk driver and locate the USB which cannot be found in Disk Management.

3.  Right-click on the disk and select "Update Driver Software" from context menu.

4.  Select Search automatically for updated driver software.

Update Driver

Wrap things up

After going through this article, now you must have learned why USB detected but not accessible occurs, as well as how to fix it in a proper way. If all the methods do not help a lot, you can directly format it via a disk formatting utility, which is usually considered as a guaranteed fix.