Computer Help forum


HDD not recognized after changing drive Letter

by windranger / January 30, 2013 6:37 PM PST

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 D:\ 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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Does it still work on another PC?
by Kees_B Forum moderator / January 30, 2013 6:42 PM PST

If not, it looks like the drive has gone south. That happens quite often with external disks. That's why you should only use it as one of your backups and to transport data to other machines or locations and never to permanently store data you don't want to lose.


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There is a problem with lower letters.
by R. Proffitt Forum moderator / January 31, 2013 12:19 AM PST

It could be in some entry for a CD/DVD/BD drive that is not plugged in. You may have walked into that old OS bug without knowing about it. It rarely pops up and if changing the letter back doesn't cure it, I see Kees told you the rest of the story.


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More info
by windranger / February 5, 2013 8:47 PM PST

The HDD is SATA; I can't rename it back because the computer doesn't see it, even in Disk Management.

The optical drive is E, there no drive assigned with D letter.

I tried it on a couple of different computers but same result.

Of course, any HDD can fail, but this problem coincided with changing the drive letter, so it's quite a low probability that the cause is different.

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by Willy / February 5, 2013 11:52 PM PST
In reply to: More info

If I remember correctly, letters A-D are supposed to reserved for drives on the system as in, "internally". This is an old coding or similar when all this came about, it helped keep the peace as it were. Which is why, in many cases, any new drive takes the next letter up that was from the line-up. In your case, this is an ext. drive and that isn't typical or you have some unique arrangement and it got hosed. I can only offer if you remove the ext. HD mounted drive inside the case and place in the PC case as 2nd or allowed connection and see what develops. Of course, SATA has it's own issues and that may refer to the reserved address for SATA 0-4 or any RAID/network arrangement if so used. You gave little details on your PC and setup, it really only a guessing game. However, not recognized on another PC, suggests that the ext. HD got labeled and thus got hosed. Since, you can't change it back other than trying the solution I offered, then you fell into a catch-22 situation. What may have happened, is you probably dismounted the ext. HD too early or some improper action and you now have the result. Have you drive mapped anything before and now a conflict arises?

-OR- if I'm following the above link actions right, you labeled the ext. HD = D, but as they provide
>>>> NOTE: It is best to select a letter between M and Z (inclusive). If you pick a letter like E, F, or G, the drive letter may still change frequently because these letters may be used for other drives, like CDROM drives, that are not always connected. <<<<

Notice the range A-D wasn't mentioned as I stated that's reserved for typical setups.

Can you take a "snipet" in Win7 of your disk management display and post on a free picture website, like Photobucket? Do your setup and then show result and snipet of display in question and post it. It helps alot to see what you really have. Post the link to your free public viewing of that pix.

tada -----Willy Happy

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Thank you.
by R. Proffitt Forum moderator / February 6, 2013 12:02 AM PST
In reply to: Letters

Around the office folk are OK with "don't do that" but here folk need a little more. Thanks for the longer post.

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I've always had good luck with drive
by VAPCMD / February 6, 2013 8:43 AM PST
In reply to: More info

letters by assigning optical discs to drive letters way down the R and S.

Using this method I can add a second or third HDD with multiple partitions and never have a problem bumping the optical drive letters.

I'm wondering if you might have hidden partition that's using drive letter D.

Use disk management to check what drive letters are being used.

Then try shifting the CD/DVD drive to letter R or S. Then recconnect the USB drive and see what it does.


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