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Author Topic: Wrong drive letters on Dual Boot System  (Read 4627 times)

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ALAN_BR

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    Wrong drive letters on Dual Boot System
    « on: July 28, 2010, 05:27:06 AM »
    My 7 year old XP laptop has just received EasyBCD and a new partition with W7.

    I now realise that the new partition has stolen a letter F:\ which has always been used for a special partition on my external Hard drive, and I want it to stay that way.

    I believe drive letters are only held in the registry and have no effect outside the O.S. in question, therefore W7 will not be affected by me changing the letter which XP uses to view it.

    Please confirm it is safe, or explain my error.

    Regards
    Alan.

    Allan

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    Re: Wrong drive letters on Dual Boot System
    « Reply #1 on: July 28, 2010, 05:37:03 AM »
    What is on f: Drive? And what do you mean the partition "stole the letter f:"? What did you do that reassigned drive letters?

    ALAN_BR

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      Re: Wrong drive letters on Dual Boot System
      « Reply #2 on: July 28, 2010, 05:49:19 AM »
      Not really stolen - just squatter's rights ! !

      I normally have the external drive switched off unless I am archiving files etc.

      Hence once I created the new partition with a Boot CD and installed W7 in the new partition, the external drive was unknown.

      I now realise that when I booted XP with the new partition present, it allocated the next available letter, and unfortunately considered F:\ to be free and available.

      I intend to change it from F:\ to some other letter that will cause no grief,
      so that the next time I boot into XP it will be able to allocate F:\ to the correct partition on the external drive, just like it always did.

      Alan

      Allan

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      Re: Wrong drive letters on Dual Boot System
      « Reply #3 on: July 28, 2010, 05:52:31 AM »
      1) As you now know you cannot have any external drives attached when installing an OS.
      2) Either leave it as is or start again - delete the partition and reinstall W7 where you want it.

      ALAN_BR

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        Re: Wrong drive letters on Dual Boot System
        « Reply #4 on: July 28, 2010, 07:30:04 AM »
        I hope we just have a misunderstanding.

        XP is installed on an 11 GB primary (not logical) partition at the start of the disc.

        W7 is installed on a 20 GB logical partition, with 3 other non system partions between it and the 11 GB partition.

        W7 refers to its 20 GB partition as C:\
        and refers to the 11 GB primary partition as D:\

        XP refers to its 11 GB partition as C:\
        and I assume that after creating the new partition then had the external drive been plugged in when XP booted it would have NOT considered F:\ to be the next available free letter, and would have chosen a letter that avoided future conflict.

        I merely wish to correct my lack of foresight and change the letter F:\ which XP allocates to the 20 GB W7 partition.
        W7 knows that its 20 GB partition is and always shall be C:\ to itself
        and is not (so far as I know) concerned that XP calls the W7 partition F:\

        XP, W7, Linux etc. all read the same "label" on a partition, and if any one of them change the label all the other O.S. will see the new label.

        I believe what XP or W7 calls a partition is a private matter within its own registry, and a change of a "private nick name" letter by XP should have no effect and be invisible to W7 - I hope, but I am here just incase I have overlooked something.

        Regards
        Alan

        Allan

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        Re: Wrong drive letters on Dual Boot System
        « Reply #5 on: July 28, 2010, 07:43:27 AM »
        1) Whichever OS you boot will see its drive as c:, regardless of the actual drive or partition designation
        2) Changing the drive letter of a drive or partition containing an OS can cause problems. Hence my recommendation above - either leave it alone or delete the partition with the "second" OS (on F:) and reinstall it on the partition you want.

        patio

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        Re: Wrong drive letters on Dual Boot System
        « Reply #6 on: July 28, 2010, 07:43:47 AM »
        A few observations:

        OS's do not change or steal their drive letters just by chance...

        You stated the following:
        Quote
        W7 refers to its 20 GB partition as C:\
        and refers to the 11 GB primary partition as D:\

        XP refers to its 11 GB partition as C:\

        Perfectly normal...when you boot to an OS it will always show itself as being on C: and the other OS as being on D or another drive letter...

        NOTE: The drive letter designations are not stored in the registry per se...they are part of the bootloader and system ini info and are created at the time of installation...

        If you are unable to make these changes from within EasyBCD then i'm afraid you are out of luck and would have to as Allan stated re-install Win7 with the external unplugged....if it asks if you want to install to what it calls F: simply say no and select another drive letter...

        You should post a screenshot of your configuration from Disk Management...
        " Anyone who goes to a psychiatrist should have his head examined. "

        Allan

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        Re: Wrong drive letters on Dual Boot System
        « Reply #7 on: July 28, 2010, 07:46:01 AM »
        20 seconds can make a world of difference  :o  ;D

        patio

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        Re: Wrong drive letters on Dual Boot System
        « Reply #8 on: July 28, 2010, 07:50:00 AM »
        I'm still up 9 to 7 if my memory serves me correctly..... 8)

                                  :P
        " Anyone who goes to a psychiatrist should have his head examined. "

        Allan

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        Re: Wrong drive letters on Dual Boot System
        « Reply #9 on: July 28, 2010, 07:50:37 AM »
        Elephant!

        ALAN_BR

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          Re: Wrong drive letters on Dual Boot System
          « Reply #10 on: July 28, 2010, 12:23:49 PM »
          I am not an elephant - I have difficulty remembering what I did last week ! !

          Here are screen shots from Disc Management of W7 showing what it sees before it ever knew that an external drive existed, and then after the external drive had been connected and W7 had installed a couple of USB bridge drivers etc and been given the reboot it requested.

          I will follow this post with a longer one showing screen shots from Disc Management of XP, together with further explanations and questions.
          This will take a little time ! ! !
          Please be patient.

          Regards
          Alan


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          Allan

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          Re: Wrong drive letters on Dual Boot System
          « Reply #11 on: July 28, 2010, 12:38:53 PM »
          I am not an elephant - I have difficulty remembering what I did last week ! !

          Sorry Alan, that was for patio not you.

          ALAN_BR

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            Re: Wrong drive letters on Dual Boot System
            « Reply #12 on: July 28, 2010, 02:19:05 PM »
            Allan, no need to apologise - I immediately realised you were taking a friendly poke at Patio and his comment about his memory.
            Regrettably my memory now gives me the choice of deciding whether to laugh or cry ! !
            I choose to laugh.

            I think I was guilty of premature excitement.

            I panicked when I saw in XP Windows Explorer that a partition "Windows 7" had taken squatter's rights over drive letter "F" which belongs to the external drive I rarely connect.  Taking the screenshots of Disc management it is not so bad after all.

            Last week is still in a mist of forgetfulness, but I now remember that on Saturday I created the 20 GB partition for Oracle VM Virtual Box to accommodate a W7 "installation", and I allocated letter M:\ so XP would still be able to use the drive letters already assigned to the external drive partitions.  Regrettably Virtual W7 took 1 minute to actually launch Windows Explorer.  Virtual W7 was in a stupor, almost none of the processor cycles did any work for me.  When I shut it down it almost shut - then told me there were 16 updates that it would first install and it took me 90 minutes past my bed time waiting.

            On Monday I gave up on Virtual W7 and purged drive M:\ to give a real W7 a home for a proper installation, and that worked well.  Instantly updated and Windows Explorer quite rapid.  Then Acronis was installed to create backup images and for that purpose a 15 GB partition was added.  That was where I made my mistake.

            I created the 20 GB partition with Partition Wizard 5.0 running under XP, and I seized the opportunity to give it letter M:\ so that the external drive would still have all the letters previously used.  My mistake was that I failed to reboot the system from W7 and into XP to add the 15 GB images partition, in which case I would have allocated letter N:\.  Instead I used the Partition Wizard Boot disc which of course gives no opportunity to assign a drive letter.

            I now realise that W7 did not "steal" letter F:\ - it was XP having one of my "senior moments" and forgetting that F:\ was (at least in my view) supposed to be reserved for the external drive, and when it saw a new 15 GB partition it seized the first letter in the alphabet which appeared to be out of use.

            A few months after I bought the external drive it lost everything.  I do not know why it died.  Fortunately my son told me that drive letters can get lost and Disc Management might fix it so I did not have to post it back to Play.com - He was right.  Trying to remember which letters had been assigned to which partition sizes was a challenge to my memory, and once I got it right I modified all the labels to remind me if I every suffered the same fate again.

            Hence you will see in sshot-174.gif that what were drives J:\ and K:\ are still correct, but disc 1 drives F:\ G:\, and I:\ have all been renamed.
            N.B. XP uses Acronis v11 which has put 120 GB of images on drive I:\.
            Acronis is a bit touchy at the best of times, and will not be amused that drive I:\ is now a mere 60 GB with no images ! !

            Long story short :-
            Premature panic;
            W7 as installed fully compatible with XP,
            even though Suzanne's IPOD is drive F:\ as seen by W7, whilst XP always has and will call it drive S:\
            W7 accepted as Drive K:\ a new 15 GB partition which XP had never seen or allocated a letter to.
            Now that XP has seen the new 15 GB partition it has accepted it as Drive F:\.
            W7 seems to work the same since XP called the 15 GB partition F:\,
            so I sincerely hope that it will be just as tolerant if I now tell XP it should no longer be F:\ but N:\

            Please confirm that I should be lucky, or explain what could go wrong.

            Regards
            Alan



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