By Cherry / Last Updated February 24, 2020


“I’ve plugged a external hard drive on my Windows 7 and Windows 10, both have the same situation that the device has been detected, but isn’t shown on explorer. Thus, even the external hard drive recognized, the files can’t be accessed. But I really need to access to it for the important photos and documents. Is there any one can help me? Any help will be appreciated in advance.”

Why it happens?

One of the most common error messages that make the hard dive inaccessible is “Hard drive is not accessible. Access is denied”. Well, there are many reasons would cause external hard drive recognized but not accessible. Like the following reasons:

1. The external hard drive may be a new drive without any partition on. If the external hard dive is a brand-new hard drive, and there is no partition on the drive, the system cannot recognized the drive size, which would cause the hard drive detected but not accessible.

2. It is too old of your driver software. You may find your external hard drive recognized in Device Manager, but not in Disk Management.

3. Encrypt external hard drive with Bitlocker. If you use Bitlocker to encrypt your hard drive, you may meet the problem that external hard drive recognized but not accessible and your important files cannot be used.

4. Besides, there are many other reasons could cause your external hard drive inaccessible, like hard drive broken, the USB power supply of removable device is insufficient, etc.

How to solve external hard drive recognized but not accessible?

To avoid data loss, you should backup the external hard drive before any operation.

As for so many different situations would cause the error occurred, you may try more than one solution to fix it. If you get the error message that “The hard drive is not accessible. Access denied”, you can try the following solutions for solving different situations.

Solution 1: for the new hard drive without any partition

If you meet the problem that cannot access the external hard drive, you can open Windows Disk Management to see whether it is a new hard drive without any partition. If there is no partition on the hard drive, then, you can partition hard drive, so that it can be accessed normally.

* If this could not solve your problem, you can fix the error with next solution.

Solution 2: for driver software not update

If your external hard drive (USB flash drive) is visible in Device Manager but not in Disk Management, and you cannot access the external hard drive. Then you can try to update the USB flash drive driver to see if it helps.

1. Open “Computer”, select “System Properties”.

2. Click “Device Manager” -> “USB Controller”, click “+”, and you will see a yellow exclamation mark.

3. Right click it and choose “update driver software”, click “automatically search for drive software online...”

Wait the update progress and let the driver to be installed, and then, reboot the computer. Then, reconnect the USB drive to the PC and check whether it can be accessed.

Solution 3: for hard drive errors

If your external hard drive is suddenly no longer operational on your computer, you can make use of the error checking tool to overcome this problem by navigating to Properties ->Tools -> Check Now. If you are fortune, your hard drive may be accessible after checking. On the contrary, you may still get the error message “hard drive is not accessible. Access is denied”.

Solution 4: for BitLocker Drive Encryption

If you cannot access the external hard drive because of the BitLocker Drive Encryption, then, you need to change the BitLocker Encryption Service.

1. Press Win + R simultaneously, typeservices.msc, hit Enter. It will open the local services page.

2. Here, Find BitLocker Encryption Service, double-clickProperties.

3. In the Properties page, change the Boot Type into AUTO, clickOK.

4. Reboot BitLocker Drive Encryption Service.

Thus, you may access your external hard drive.

Solution 5: solve hard drive inaccessibility issues by formatting

To solve external hard drive recognized but not accessible problem, formatting will be the sure shot way. If all above ways cannot solve the external hard drive is not accessible problem, you should format it. However, you may face the big problem that formatting will cause your data loss permanently. Fortunately, you can try to use the free hard drive data recovery tool iBoysoft Data Recovery to recover data from inaccessible hard drive. Once your files are recovered, you can access your data again. So, you can go ahead to format the inaccessible hard drive without worrying about data loss.

To format external hard drive, here we highly recommend you a hard drive format tool AOMEI Partition Assistant Standard, which allow you to format external hard drive easily ad simply. And here you can learn how to format external hard drive with AOMEI Partition Assistant.

Step 1. Connect the external hard drive to your PC, make sure it can be detected.

Step 2. Free download AOMEI Partition Assistant, install and launch it.

Download Freeware Win 10/8.1/8/7/XP
Secure Download

To format the inaccessible drive, here you need to right click it, select Format Partition.

Format Partition

Step 3. Then, it will pop up a small window where you can set up the detailed of formatting. You can format the external hard drive to FAT32, NTFS, exFAT, Ext2, Ext3, etc. Choose one and click OK.

Partition Label

Step 4. When you back to the main interface, click Apply-> Proceed.


After the formatting, you may reuse the external hard drive as a new one.

* AOMEI partition Assistant has specific edition for Windows Server users. If you are Windows Server users, you can turn to AOMEI Partition Assistant Server for help.

Solution 6: for the external hard drive is visible in Windows Explorer but cannot be accessed

Another way is to reset the permission from Windows Explorer if it is visible in Windows Explorer but you cannot access it.

1. Right click on the inaccessible drive, select Properties.

2. In the Properties window, select Security, click on Edit...

3. It will pop up a window “Permissions for New Volume” dialog box. Click the Add button to continue.

4. Then, add a new user maned “Authenticated User” and click OK.

5. From the permission section, give “full control” to newly added user and click “OK”.

6. The dialog box will show two options: “Continue” or “Cancel”.

7. Press Continue… and Cancel at last.

Now, you are done, and you can reboot your computer to check whether you can access the external hard drive successfully.


This article provides different solutions for different situations of “external hard drive recognized but not accessible. Actually, there are more than one error for hard drive is not accessible. You may meet many other errors such as “Drive is not accessible. The parameter is incorrect”; “Drive is not accessible. The volume does not contain a recognized file system”. “Drive is not accessible. The disk structure is corrupted and unreadable” etc. If you have any great solution or any new question, welcome to write to our comment area. We can fix it out together.