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I/O device error while trying to rebuildbcd on Win 7

Anonymous
2013-01-03T14:43:16+00:00

Hello,

recently my computer could not boot and it said "bootmgr is missing" on the screen.

After looking for help I downloaded a repair disc and used the startup repair. A problem was found but could not be automatically fixed.

So I started bootrec.exe, rebuildbcd found 1 windows installation. When trying to add it to the bootlist command prompt said it was impossible due to an I/O device error. I also tried selecting several partitions as active.

The problem is I can just boot off that repair disc, is there any way to fix that error from the command prompt perhaps?

Thanks for your help!

Windows for home | Previous Windows versions | Windows update

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  1. Anonymous
    2013-01-28T18:11:35+00:00

    Hello,

    I entered chkdsk /r in the command prompt and the computer started working again. Thanks!

    It has been working for approximately 3 weeks now and 2 days ago it got extremely slow.

    I ran a check with Norton Antivirus which resulted in nothing. Last night I was trying to boot, the logo popped up on the screen and froze. I ran chkdsk /r over night and it stopped at 11% of phase 1.

    This morning I was able to boot but could not boot this afternoon since it froze again while booting.

    Startup repair tried to fix it but did not help.

    What would you recommend?

    Should I paste the error code from startup repair?

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  2. Anonymous
    2013-01-04T20:41:21+00:00

    I started in safe desk and entered chkdsk /r into the command prompt. The first two stages went through pretty quickly but it has been stuck at stage 3 of 5 for several hours.

    CHKDSK found several unindexed entries and indexed them. Afterwards I restarted and the Bootmgr is still missing.

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  3. Anonymous
    2013-01-04T07:42:34+00:00

    Hi John,

    Thank you for reaching out to the Microsoft Community!

    I am sorry to know that you are getting an error “I/O device error” while trying to rebuild BCD on Windows 7.

    The most common cause of a non-accessible I/O error is a disconnected cable. When the computer tries to access a device and it gets no response after several tries, it will generate this type of error. Another common cause is when a program tries to access a file that has been removed or deleted.

    Disconnected Hard Drive/Incorrect Cable Setup

    Internal drives require a specific set up. IDE hard drives can only have one master. If another hard drive has its pin setting set incorrectly, a user might not be able to access the data, and he will receive a message that the drive cannot be accessed. Cables coming loose inside a computer's case also cause a non-accessible I/O error. The user can fix this problem by opening the case, and attaching the data cables for each drive securely to the motherboard and to the back of each drive.

    Method 1: Test the issue in Safe mode and perform check disk.

    Check if you receive those error messages in Safe mode. Visit the link below to know how to boot the computer in Safe mode.

    http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

    **Step 1:**Start your computer in safe mode with command prompt and then perform the following steps:

    Perform a check disk operation:

    a.   In the command prompt, change the location to c: and then type chkdsk /r and press Enter.

    Note 1: Answer Ywhen chkdsk asks you if you want to check the drive next time Windows boots (restarts).

    Note 2: /r = The /r switch tells chkdsk to attempt to recover any bad sectors of the hard drive if any are found. A bad sector is a spot on the hard drive that cannot hold saved data anymore. If you’ve any data on that sector, you’ll lose that.

    Note: While performing chkdsk on the hard drive if any bad sectors are found, it tries to repair that sector and if any data available might be lost.

    If the issue persists or you have further questions on Windows, do not hesitate to let us know. It is our pleasure to be of assistance.

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