Windows 7 Forums
Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.

Windows 7: Not recognising USB HDD,s

02 Mar 2015   #1

Win 7 home premium x64
Not recognising USB HDD,s

Hi all.

As of a few days ago, computer not recognising plugged in USB hard drives.
Have to assign drive letter via Disk Management to access the drive.
I don't understand why this should suddenly occur. I am not aware of anything untoward happening that results in this very annoying glitch.
Ideas most welcome.

Thanks in advance.

My System SpecsSystem Spec
02 Mar 2015   #2

Microsoft Community Contributor Award Recipient

Windows 7 Home Premium SP1, 64-bit

Here's some ideas:

Use another cable

Use another USB port

Run the drive manufacturer's diagnostic tool

Not sure what drivers USB drives use, but you might try to remove any drivers in Device Manager and then do a new install as if you just bought the thing.
My System SpecsSystem Spec
02 Mar 2015   #3

Win 7 home premium x64

Should have been more coherent. The drive does show in Disk Management but drive letter is not assigned and therefore it is not accessible in win explorer for example, until drive letter is assigned. This happens with all my USB drives regardless of port used.
My System SpecsSystem Spec

02 Mar 2015   #4

Windows 7 Home Premium 32 bit

Your early morning worksheet. :)

Plug out all USB HDDs.

Start > All Programs > Accessories > Right click on Command Prompt and Run as administrator.
diskpart [ENTER]
Against the DISKPART prompt
automount [ENTER]
Does it say "automatic mounting of new volumes disabled" ? Then
automount enable [ENTER]
"automatic mounting of new volumes enabled"

Close Command Window.

Now plug-in your ext. HDDs

Problem resolved??? Post report.
My System SpecsSystem Spec
02 Mar 2015   #5
Layback Bear

Windows 10 Pro. 64/ version 1709 Windows 7 Pro/64


Would it be helpful after following your instructions to reboot?
My System SpecsSystem Spec
02 Mar 2015   #6

Windows 7 Home Premium 32 bit

Usually we always recommend to reboot after doing any alteration. Some do not require a reboot.. I do not remember whether a reboot is required in this case. I have to run it and check. You may also disable and then enable and check. Thanks for bringing this out . To make sure, the OP may reboot and then plug in his HDDs.
My System SpecsSystem Spec
03 Mar 2015   #7

Win 7 home premium x64


Followed your instructions and indeed auto mounting was disabled.
All external HDD's now have drive letters attached.
I would like to know why auto mounting was disabled, but I suppose that's Windows for you.

Thanks a lot.
My System SpecsSystem Spec
03 Mar 2015   #8

Windows 7 Home Premium 32 bit

Quote   Quote: Originally Posted by grasmith View Post
Jumanji....I would like to know why auto mounting was disabled, but I suppose that's Windows for you.....
Neither men nor machines are 100% perfect.:)

Some random event had caused the registry value HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MountMgr\NoAutoMount to change
from 0 to 1 . We just reversed it.

What that event was in your case is hard to guess.

In Nov 2014, when Lady Fitzgerald was setting up her new Lenovo laptop, she had the same problem. Considering that it was a brand new laptop, it is even harder to guess.:)

Anyway, I have added your question to the "100 things to do research" list, but I don't know when I will do it. I am not perfect either.
My System SpecsSystem Spec

 Not recognising USB HDD,s

Thread Tools

Similar help and support threads
Thread Forum
USB 3.0 not recognising anything
I've just finished building a PC, and the mobo's CD installed some of Intel's USB 3.0 drivers. They seem to be up to date, as I have tried updating them via Gigabyte and Intel's website. However, whilst they provide power, they will not recognise any drives. My Device manager is shown below ...
Hardware & Devices
Win7 not recognising new 3rd HDD
The BIOS sees it. System Info for Windows sees it, but shows no drive letter. Device Mangler lists all 3 drives, but is not much help because Properties shows no Volume or capacity for any of the HDDs. Can I assume this drive is an unformatted blank? How do I format it if Win is not seeing it? ...
Hardware & Devices
cd drive not recognising certain cds
my cd drive doesnt recognise certain cds but will recoginse others. the cd it wont recognise is brand new so there isnt anything wrong with the cd itself
Hardware & Devices
Windows 7 dvd not recognising HDD
Hi guys......I am having a serious problem with my Sony Vaio E series laptop. All of a sudden when I was skyping with my friend, it hung up. So I forced shutdown. Then it could not load windows 7 and asked for start repair. Tried to do that but after hours of repair it said 'Operating System not...
BSOD Help and Support
Only recognising 1GB RAM
Hi I have just upgraded to Windows 7 from XP... I have 2GB RAM installed on my laptop but for some reason Windows 7 is only recognising 1GB ?
General Discussion

Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 15:11.
Twitter Facebook Google+