SFC /scannow remove Dual Boot?

Discussion in 'Computer Software and Operating Systems' started by DismissedGuy, May 13, 2017.

  1. DismissedGuy

    DismissedGuy Advanced Member

    Aug 15, 2016
    Hey guys,
    Last night I started my pc from standby (windows 7) and I saw it was running an sfc scan. I dunno why this happened, but I let it go and when it was done it told me that there were corrupted files found and it will try to fix them on the next reboot.
    Problem is, I'm afraid that these "Corrupted System Files" are actually the boot manager replaced by GRUB... I'm running Ubuntu alongside windows, and I don't like windows to repair it's full boot manager and not letting me boot in Ubuntu anymore.
    I managed to get the log file from %windir%\logs\CBS\CBS.log, and it's attached to this post.
    Will it overwrite the boot manager, and if so, is there a way to prevent it from repairing on boot?
    Not going to restart my laptop before that :/
    I changed the CBS.log to CBS.txt to upload it here, but it will still show the same content.
    Thanks in advance!

    Attached Files:

    • CBS.txt
      File size:
      1,011.5 KB
    Last edited by DismissedGuy, May 13, 2017
  2. Felek666

    Felek666 retarded memekid which no one likes

    Jan 3, 2017
    If it does it on boot, then it's probably a BIOS firmware which is doing that.
  3. The Real Jdbye

    The Real Jdbye Always Remember 30/07/08

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    Mar 17, 2010
    If you're using UEFI you can simply add the grub efiboot file to the Windows boot manager and you won't have to deal with that.
    If you're not using UEFI I seem to recall EasyBCD has an option to install a grub4dos boot manager that will let you boot back into Linux. The last option is booting a Linux live CD and reinstalling grub from there.
  4. DismissedGuy

    DismissedGuy Advanced Member

    Aug 15, 2016
    It told me something like this:
    "There are corrupted system files found, but not all of them can be repaired."
    and a few lines later:
    "the changes for repairing the sytem file will not be applied until the next reboot."
    I'm not a computer master, but it seems strange to me this has something to do with the BIOS.
    EDIT: And... How do I check if my system has UEFI or not without rebooting into the BIOS? For example, if it DOES overwrite bootmgr, it is too late to change anything to grub, because it is probably already overwritten. I had a few times with windows that it just skipped GRUB when installing updates...
    I already tried searching for the setupact.log file, but apparently I don't have it.
    Last edited by DismissedGuy, May 13, 2017
  5. Joom

    Joom  ❤❤❤

    Jan 8, 2016
    United States
    Even if it does overwrite GRUB fixing it is a walk in the park. All you need is an Ubuntu Live USB to boot from, and do the following (assuming that your Ubuntu partition is sdb).

    mount -t ext4 /dev/sdb1 /mnt 
    grub-install /dev/sdb
    grub-mkconfig -o /mnt/boot/grub/grub.cfg
    Modify this accordingly if your partition letter and filesystem is different.
    VinLark likes this.
  6. DismissedGuy

    DismissedGuy Advanced Member

    Aug 15, 2016
    I just rebooted, and it didn't overwrite GRUB. However, after reboot, I runned another SFC scan (manual this time) and it left EXACTLY the same log file, except for the timestamps, where the milliseconds only were the same. Always knew Windows was a bit crazy sometimes, but just copying a log file and editing the timestamp hours, mins and secs only...
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