Unable to run two drives at same time

Unable to run two drives at same time

Hi Guys !

I have 2 identical Drives    " My Book Essential 2.0 G ( 1.8 G )  "  bout drives I know are in good shape , runs perfect if I was connected by itself . BUT run just one if two was plugged!

This problem never happened before i  

I have more drives (different sizes) and many times i connected more than 2 at same time… And no problem!

I connected to another machine and the same problem… just one run the other looks like run the lights go on etc. … But files never appear   and don’t shows under my computer section just the one running i

If open the Computer management under Drives appears and shows just the available space and a question mark Under drive … i try to Re-scan the drive and nothing happens!

I used windows 7 in bout machines!

 Any idea?     


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With both drives connected go into Disk Management and you will probably see one of them doesn’t have a letter. Give that one a new letter and make sure its Online.


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I had the same problem my second hd was offline . thanks

Ok …first thanks for answer and you are correct the drive don’t show a letter ID … just the volumen size and shows OFF line …

and  I find a 2 solutions , one thing is just temporal and the second is the correct way .

lets go to the first solution and works for me … ( thanks to “Sarabh” for the tip )

1- Go to Computer Management and Click   “Disk Management”  to display all the drives… and look for the drive to shows OFF LINE  , point the cursor over the ? mark and a message apears … in my case says … ( The disc is Off line because it has a signature collision with another disk drive that is online ) …

Now RIGHT click on the OFF LINE message and a options pops …click or select ON LINE DISK … the disk star scaning and  works …

but that in my opinion is just a temporary solution … because the conflic ID signatures  … for that a have this solution… but I really don’t know HOW to use the comands … I have a lot of information in drives and more panic to lost them

I just copy paste this info from the net

The disc is Off line because it has a signature collision with another disk drive that is online

How to Fix the Disk Signature Collision Problem in Windows 7

Windows 7 comes with a command line utility called diskpart that can let you view and change the disk signature.

    Open a command prompt as administrator. To do this in Windows 7, click the Windows start menu (the round Windows icon on the left bottom corner), type “cmd” (without the quotes), right click the “cmd.exe” item that appears at the top of your menu, and click the line “Run as administrator”. Do this even if you are already logged in as administrator, since on Windows 7, administrators run with reduced rights by default.

    A black command prompt window will open. In Windows 7, the title bar of the window will tell you that you are running it as Administrator. If it does not, it means you did not do what I just said above. Return and follow the first step, or you will not be able to successfully carry out the rest of this tutorial.

    Type “diskpart” (without the quotes) into the window. (Note: for this and the other commands described here, you’ll have to hit the ENTER key after you finish typing your commands for them to take effect.)

    Microsoft DiskPart will start. When it is ready, it will issue a “DISKPART>” prompt, allowing you to enter your commands.

    Type “list disk” (without the quotes). This will list all the disks that are currently mounted (connected to the system). The disk will not have the usual names and labels that you’re accustomed to from the Windows Explorer interface, so you will have to recognize them by their sizes.

    Note that “list disk” actually lists the physical disks, and not the partitions that you may have assigned drive letters. This means that if you have 2 physical disks, with 3 partitions on each, so that you have drives C:, D:, E:, F:, G: and H:, “list disk” will only show “Disk 0” and “Disk 1”.

    To view the signature of a disk, you must first select it. To select a disk, type “select disk x” (without the quotes) where x is the number of the disk from your “list disk” display. When you type (say) “select disk 1”, DiskPart will respond by telling you “Disk 1 is now the selected disk”.

    Now type “uniqueid disk” (again, without the quotes). DiskPart will respond with the disk’s signature, a series of hexadecimal digits (or at least I think it’s hexadecimal).

    To change the signature to some other number, type “uniqueid disk ID=[NEW SIGNATURE]” (without the quotes) where “[NEW SIGNATURE]” stands for the new identifier you want for the disk (without the square brackets and without the quotes). However, before you do that, you may want to type “help uniqueid disk”, which will give you more information on how the command works. You may also want to find out the disk signatures of your other disks on your system before you modify your current one so that you don’t cause a new signature collision in trying to solve your current problem. In addition, if you’re really not sure how many digits you should give your disk, perhaps try changing only one digit of the current signature (eg, increasing or decreasing it by 1). Remember my disclaimer above: I really don’t know what I’m talking about here: do it at your own risk.

    To quit DiskPart, type “exit”. Incidentally, in case you get lost while running DiskPart, when you are at the “DISKPART>” prompt, you can type “help” to get a list of commands. Typing “help” followed by the command typically gives you more info about that command.

    Once you’ve quit DiskPart, type “exit” again to quit the Administrator Command Prompt.

the Orange section is the one to don’t undertand or how to change the SIGNATURE ID ?