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Windows 7: External HD not showing on my computers

29 Dec 2011   #1

windows 7 home prenium 64bit
External HD not showing on my computers

Hi. What do I do if?

My Dad's External Hard drive is pluged into my windows 7 computer and is not showing on "my computer" or "disc management". The External HD has been used on another computer which is xp. Then I decided to watch movies and plug it into mine. Not sure why I can't see it. Exactly the same problem as this: External Hard-Drive Not Showing Up

My hard drive is HP SimpleSave 1 TB of storage.

PS: Windows 7 Home prenium 64bit

Thank you for your time.

Attached Thumbnails
External HD not showing on my computers-external-hdd.jpg  
My System SpecsSystem Spec

30 Dec 2011   #2

Windows 7 Ultimate x64, XP Mode, W8.1 Preview VM - 7 Pro x64 second remote tower

Hello realboy Welcome to the SevenForums!

I think you already found the solution by looking post #7 on the other thread. You will need to go into the Disk Management tool and may even have to review the menu bar options for rescanning drives.

Are you oluuging the drive before you start the system or after? would be one question for you. If you are plugging it in prior to powering up your system there nothing will show. Wait until Windows is finished loading and you are at the desktop before plugging it in. You should then a new hardware found pop up notification appear.

Once Windows has recognised a new device has been added on you can proceed to the DM and locate the unidentified disk and change the drive letter in the right cilck menu of options. This will initialize the drive where you should see a flashing pop up appear there briefly while Windows then mounts the volume on it as a new logical drive.

What will make detection much easier in the future once you can clear the drive of any files and see it reformatted is changing the factory exFat or Fat 32 volume to NTFS for going back and forth between two different Windows machines. However once you have a drive letter assigned that should be remembered the next time you go to plug it in.
My System SpecsSystem Spec
30 Dec 2011   #3


wow, that's bad... I have an elderly customer with XP who is used to leaving the external drive on when he boots. I was recommending to him a windows 7 system. now I am not so sure...

I don't like power-cycling the drive every time I have to use windows. switches are only good for so many toggles (power switches are good for about 10,000). after 5 years drive lifespan at 2 power cycles per day and 2 toggles per power cycle that's about 5*365*2*2=7300 toggles.

this looks like a microsoft ease-of-use blunder.
My System SpecsSystem Spec

30 Dec 2011   #4

Windows 7 Ultimate x64, XP Mode, W8.1 Preview VM - 7 Pro x64 second remote tower

That's becuase the drive has already been in use and already has a drive letter assigned to it. For any new drive being plugged in or added on the first time it needs to be detected by Windows before it can be used.

It doesn't matter which version of Windows you have on the system except Vista lacked Fat support where the drive manufacturers have their own program that will install or run on Windows so the drive will be seen. Readi Boost is common on usb flash drives for the same reason since many drives come with Fat or exFat factory volumes on them for cross-compatibility with other OSs as well as Windows.

With a drive stuffed in an external fan cooled usb enclosure here when I go to turn the enclosure's power switch on the drive then will appear in W.Explorer and Computer immediately after the first minute in WE. The drive realboy is referring to is being shared between two systems for the first time now and needs to be properly detected so Windows will remember it later the next time he goes to borrow it.
My System SpecsSystem Spec
30 Dec 2011   #5


well, the situation of having a perfectly-set-up usb drive suddenly stop working because you booted with the drive on doesn't seem to be good at all. I am not sure what you are saying - it sounds as if you are saying that it is normal for windows 7 to obliterate external pre-configured drives when windows boots. (?) I am a little confused here.
My System SpecsSystem Spec
30 Dec 2011   #6


just realized that like you said, an older xp-formatted drive won't be recognized by 7 without windows 7 doing some tweaking of the drive... sorry I am a little dense today.

I wonder what happens if you take that same tweaked drive and put it back on the xp machine or linux+ntfs-3g or mac+ntfs-3g... will it still read it? just wondering out loud... would be good to know.
My System SpecsSystem Spec
30 Dec 2011   #7

Windows 7 Ultimate x64, XP Mode, W8.1 Preview VM - 7 Pro x64 second remote tower

realboy decided to plug in the drive taken from another XP machine into his own 7 system and was asking why the drive wasn't being seen. Regardless of how old any drive or device is it's still seen as a new hardware being added on.

With hard drives, internal as well as external, usb flash drives as well each has to be initialized so Windows will be able to mount the volume(s)(partition(s)) on them. If I turn off the power on an external usb enclosure here it will be as if I unplugged the drive. When turning the power on after months of sitting idle it will still appear with the same drive letter since one had been assigned.

With usb flash drives basically you would see the same thing. I have some here reserved for data recovery and have R assigned as the drive letter. After sitting in a case for months I can plug one of them in and it will appear once again as the R drive. If I take it to another machine for the first time and it is initialized on it's own it will likely see E, F, G, H, or I as the letter given to it by Windows.

When any drive or device isn't seen immediately then you have to manually go into the Disk Management tool in order to see it initialized usually by a simple right click to pick a drive letter for it. Sometimes however when a volume isn't seen in the list of drives you have to try the rescan option to refresh the list.

This happens far more with external hard drives and flash drives when plugged in for the first time while the system is powered down and simply not detected when the machine is turned on. Internal drives IDE or Sata are tied to the onboard controllers and generally never run into that however. But with anything USB it needs a good detection when first plugged in while Windows is running.
My System SpecsSystem Spec
30 Dec 2011   #8

windows 7 home prenium 64bit

Thank you I'm giving this a try...!
My System SpecsSystem Spec

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