HDD not recognized after changing drive Letter

By Windranger ·
I changed the drive letter of an external 2.5' HDD (from F to D).

Then for some reason I suddenly can't use the drive anymore.

Now when I plug it, the error message is on Win7 is "You need to format the disk in drive"
The error on Win XP is \ is not accessible

which is quite weird.

The drive is not used much, it never had surface problems, etc.
Of course I don't want to format it because I have some info there.

Any ideas about what the problem could be...?


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All Answers

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So after you changed the drive letter

by OH Smeg Moderator In reply to HDD not recognized after ...

How did you dismount the drive?

You need to use the Safely Remove Option under all versions of Windows to Dismount the Drive or run the risk of Corrupting the Partition Tables.

You can try running Check Disc on the affected drive and it may repair the Partition Tables but depending on how Important the data on it is you may want to pay a Professional to Recover your Data. If it's only just Nice to recover the data run Check Disc without a second thought but if you must recover the Data send it to a professional as the more you unsuccessfully mess with it now the more expensive the recovery is going to be and the less likely you are to recover 100% of the data.


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What if you just change it back?

by Slayer_ In reply to HDD not recognized after ...

I think Windows likes to reserve the D drive anyways.

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Reponse To Answer

by malc In reply to What if you just change i ...

No, it doesn't. It's just the first drive letter to use, alphabetically.

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You don't mention external disk type

by Cmd_Line_Dino In reply to HDD not recognized after ...

Is it USB or eSATA or something else ?

On power up does the drive spin up and do the usual few seconds of activity ?

Is the use of conflicting with a CD/DVD/Blueray drive or chip reader or something.

On the Win 7 system...
Disconnect the problem disk and reboot
Is some device assigned to ?
Be sure to look through the lower pane list. CD, DVD etc appear only there.
If there is a then change it to some other letter.
Connect the problem drive. Is it visible at all in DISKMGMT.MSC

Try a power cycle reboot.

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Reponse To Answer

by gechurch In reply to You don't mention externa ...

That's perfect advice for the problem of a drive not showing up, but it can't be the case here. Drive letters are a first-in-wins affair. Either the external drive gets and it works fine, or it doesn't get and therefore won't appear at all. It's not possible for it to kinda-a-little get but only enough to show as needing to be formatted.

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Windows XP Drive letters

by Merlin the Wiz In reply to HDD not recognized after ...

Been there done that twice on non-CD laptop computers! Change it Back to F: and it should work. The drive designation appears to be reserved in Windows XP for a CD drive. Even if your computer does not have a CD drive.


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Reponse To Answer

by Cmd_Line_Dino In reply to Windows XP Drive letters

I suspect your experience was a function of the laptop BIOS not Windows.

I just plugged a USB disk into my Toshiba laptop (it has no CD or DVD) and the drive came up as
It is Win 7 64bit not XP.

Also on XP if you install a second internal disk drive it will come up as and the CD/DVD will be E:

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Reponse To Answer

by Slayer_ In reply to Windows XP Drive letters

Windows isn't very smart about this stuff. D could be reserved for disks or drives, but not removables.

I have a repeating example, I have in my laptop, drive C, D, F and H. E is my CD drive. I have a mapped G drive. Whenever I plug in a new flash drive, it tries to give it the letter G, and then it doesn't show because G was used by the mapped drive. So I have to go into drive management and reassign the flash drive to another letter.

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Reponse To Answer

by Cmd_Line_Dino In reply to Windows XP Drive letters


Your problem is unique to your hardware/software.
I have never had the problem you describe.
If a drive being connected cant get the letter assigned to it by diskmgmt.msc it just grabs some available letter.

Years of use, XP now Win 7, my desktop mapping drives to 3 or 4 other desktops and 2 laptops.
And on my desktop 2 eSATA drives, 4 or 5 USB drives.
A USB chip reader coming and going. It creates 4 drive letters.
Other USB drives and jump drives coming and going.

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no reserved drive letters, not even in win 2K . . .

by Who Am I Really In reply to HDD not recognized after ...

only reserved drive letters are ones already in use

you can't change the drive letter in disk management to one that is already in use

on a system with no CD/DVD drive, card reader, or floppy drive that has windows installed on the default C
you can assign A:\, B:\, or any letter from \ - Z to any other partition / drive / mass storage device
windows assigns the letters sequentially after C
thus you generally won't encounter a USB drive getting A or B
but if you plug in 23 storage devices you will have used all the letters from \ -> Z:\,
and then when you plug in number 24 you will get a drive letter assignment of either A or B

in this case however, I agree with Col
and I'm leaning more to either the corrupt partition table or a mechanical or electronic/electrical failure of the HDD or USB -> SATA/IDE chip(s) etc. in the enclosure
removing it from the USB enclosure and attaching the HDD directly to an internal connector or a known working USB adapter will give some idea about whether or not the electronics are fried in the enclosure or if the HDD has gone for a dump,

I've seen these things just go poof for no apparent reason

recently had an HDD go poof just by touching the case while it was writing
heard a click and then it was gone, (the read / write heads were immediately barbecued)
I know it was static because of the dusty & dry environmental conditions in that particular office, but I didn't even feel it leave my finger

a static blast up the USB cable while plugging, unplugging or just grabbing it can cook these devices.
even a small static blast that you might not even feel can cook toast it
a larger static blast can **** a whole trace line right out of a PCB

Removing a USB SD card reader, flash drive, or HDD without safe removal can toast the partition table,
however, even with safe removal you can still fry it electrically with static discharge

There's more than one way for these things to go poof.

if it's a partition table corruption
there are some tools available that can correct the partition table or attempt to read the data from the disk that appears as unformatted

but an electronic / electrical failure will require data recovery services

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