I am facing this situation. I have a dual boot system with Windows 10 and Ubuntu 18.04 Since yesterday, I am stuck into Windows. When rebooting, my screen stays black, until it boots into Windows again. Not going into bios or grub. So i cant even start from a bootable USB or disc. Last week i installed grub customizer, and recently I set it up to boot into the last used operating system. Any ideas, while it seems that I can't even format my disk, while i can't change boot order?
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I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu.
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I have a dual boot laptop (Windows 10). I ran general updates and now my Ubuntu won't boot.   I ran in recovery mode and still it freezes in the same place.      Kernel panic – not syncing: Attempted to kill init! exit code=0x00007f00
37132
I have dual boot configured with Windows 7 (32bit) and Ubuntu 12.04(64bit). I installed Ubuntu after windows, now my windows is corrupt due to some virus and I need to reinstall it. Currently when I start my PC, grub loader comes up and I need to select Ubuntu or Windows.   I was wondering how can I install windows again and still have my Ubuntu install? Is there a way to do this?  I do not want to install Ubuntu again and lose my settings and data there.   Thanks, Ketan
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I have a HP laptop with Windows 8.1 and Ubuntu 14.04 dual booted. I used to use F9 key to enter boot menu and chose Ubuntu and then GRUB would appear where I would chose Ubuntu again. This was working fine all this while. Either a hardware change or a Windows update has caused the Ubuntu option to go missing from the boot menu itself.  How do I fix this and boot into Ubuntu again?
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I have Ubuntu Precise beta 2 and Windows7 set up to dual boot.  The set up had been perfect, until today, with a black screen presented when trying to boot Windows with a BOOTMGR image is corrupt, cannot boot fault.  Is there any way to fix this from Ubuntu, or is a reinstall my only option?
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I installed Windows 8 and Ubuntu 12.10 on a 3TB GPT disk in UEFI mode.  Both can boot up OK.  Both operating systems created their ntries in the UEFI boot menu, there's an "ubuntu" and a "Windows 8" entry.  The boot order can be altered in the motherboard's UEFI setup.  I'd like to boot "ubuntu" first, because I set up GRUB 2 to be able to boot both systems.  But whenever I boot Windows 8, it changes the boot order so that it boots up first.  How can I prevent this?  Thanks a lot.  -- UPDATE --  I learned that bcdedit.exe can be used to manipulate the Boot Configuration Data in windows.  This is important because Windows synchronizes the BCD with the boot NVRAM, that stores the boot order.  Every time the {fwbootmgr} entry in the BCD is touched, the NVRAM is overwritten.  I modified this entry to load GRUB 2 first, and it did. However, after booting Windows 8, both the NVRAM and the {fwbootmgr} in the BCD reverted to the original order, that is, to boot Windows 8 first.  I'm really puzzled by this.  -- UPDATE 2 --  I managed to kinda fix the problem by creating a startup script at the group policy editor in Windows. The startup script issues a "bcdedit /set {fwbootmgr} DEFAULT {appropriate UUID}" command. This is BIG hack, and definitely NOT the soulution I want. I'd like Windows to feel OK at the second place after GRUB in the NVRAM.  So how can I do that?
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I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?
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I have a computer which is currently running Ubuntu 14.04. I would like to dual boot with Windows 8. I can not find any instructions for installing Windows after Ubuntu is already installed. I am only finding instructions for doing the opposite, Installing Ubuntu after Windows 8.
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I followed this  to install Ubuntu as dual-boot with Windows 8.1 pre-installed as(UEFI),but I am not able to dual-boot and tried    I first burned an Ubuntu ISO on a blank DVD-R to create the LiveCD. Even with secure boot disabled, when I tried restarting my computer, it never booted to the installation screen, and it just skipped to Windows.  After a lot of skimming, I thought I had to put my computer in Legacy Mode in order to get give my CD/ROM drive priority. I installed Ubuntu and used my existing EFI partition. Ubuntu works, but Windows doesn't, probably because my laptop is stuck in Legacy Mode. I tried switching back to UEFI using boot-repair on the Linux Terminal, and going into Advanced Properties -> Grub Location -> Ticking the checkbox for EFI, but it says I need to be in an EFI session, and now I'm just really lost and confused at what I've all done. I can see my Windows8.1 OS on a partition but I want to dual-boot Windows 8.1 along with Ubuntu?   Did I just brick my computer?
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Trying to install ubuntu on a laptop. The "bios/uefi" has no uefi boot options &amp; the windows boot manager just kicks in. The only "option" is "boot from hard disk". So we tried to use efibootmgr to put grub to boot first.  When we run an efibootmgr -o xxxx,xxxx,xxxx command it seems like the order gets fixed but on reboot the windows boot manager still has control, then when we re-opened the live usb &amp; checked the boot order it remains unaffected.  What are other ways to change the efi boot order? Maybe by mounting the efi partition (in mnt) and doing what?
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After installing the Windows 10 upgrade on my laptop, it ruined the grub boot manager, and I could only boot in windows 10. I fixed the boot manager using a live cd with the boot-repair tool, but it only recognized the Ubuntu partition, and not the Windows one.   So I edited the /etc/grub.d/40_custom file and added the following contents:  menuentry "Windows 10" {     set root='(hd0,3)'     chainloader +1 }   After running sudo update-grub2, I got an entry in the boot menu, but the partition does not load. It gives the following error:  Error: Invalid signature.     Does anybody know how one can overcome this error?   My most recent boot-repair dump is here: , and the partition I want to boot is this one:  sda4: __________________________________________________________________________      File system:       ntfs     Boot sector type:  Windows 8/2012: NTFS     Boot sector info:  No errors found in the Boot Parameter Block.     Operating System:       Boot files:        /bootmgr /Windows/System32/winload.exe
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I have an Ubuntu 12.04 / Windows 7 dual boot. After installing Ubuntu my computer reboots straight to Windows. There is no option to boot Ubuntu.  Specs:   OS: Windows 7 Home Premium     CPU: Intel i5 2500k     mobo: ASUS P8Z68-V Pro     GPU: GeForce GTX 570      SSD: Corsair 120GB (Windows 7)     HDD: WD 1TB      I select the USB drive in the BIOS and boot to it and choose install. I select to manually configure partitions, partition the 200 GB of unallocated space on my 1 TB HDD into 16 GB swap file, 30 GB / ext4, and 154 GB /home ext4.   I made sure that the bootloader is installed on the Corsair 120GB SSD (where the Windows boot is) and the installation goes smoothly.  When I reboot after the install it runs through the BIOS straight into Windows. I have tried upwards of a dozen times and I have also tried with Linux Mint. I have also redownloaded the ISO and used two different programs to create the live USB.   The installation seems to have gone well, as after the installation I can see the partitions I have created in Windows Device Manager.       I currently run Lubuntu on my laptop, but it is not a dual boot. I'm assuming this is a bootloader issue and I am assuming that inside those partitioned files in my screenshot there is a working Ubuntu 12.04. I just have no way of getting to it.    Update: (copied from comment)  I booted using my Ubuntu live USB and used the Boot-Repair tool suggested in .   Upon opening the tool I saw that it was recognizing my SSD as a removable drive and defaulting to install on the HDD. Once I realized that I was able to force install onto the SSD. My computer can now boot Ubuntu.
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I have Windows 8 Release Customer Preview on my laptop. I tried to install Ubuntu on it with Ubuntu Windows installer (I have always used this to install, although that was on Windows 7), it installs and asks to reboot, then immediately Windows 8 boots up.  I do not have the option to choose what OS to boot. How can I boot to Ubuntu? VM is not exactly what I would like to use, but it is an option, however a last resort. Any help?
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I have a dual boot setup:   Ubuntu 16.04 LTS Windows   Currently when I want to reboot from Ubuntu into Windows I use grub-reboot with the appropriate number as argument. This works well.  However sometimes Windows needs a reboot so a certain program can install or update and I manually have to select the right grub boot menu entry. Is there a similar way (from Windows UI) to tell grub which entry to boot?  I suppose the grub-reboot command passes the argument to a file which is in turn read by grub upon reboot.  edit (concerning my selected answer): I'm currently looking into mounting the ext4 drive that contains /boot and scripting the edit. this will possibly take quite a while since i'm doing this in my free time beside my 40h/week non-tech job. ^^
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I have a Sony VAIO S series with Windows 8 preinstalled, and I installed Ubuntu 12.10 on a new partition. When the PC boots Grub is display, and I can choose between Windows 8 (didn't worked at the beginning, had to change Grub settings) and Ubuntu 12.10. When I select Ubuntu 12.10 everything is OK, but when I use Windows 8, and I restart Grub isn't displayed anymore (Windows 8 boots immediately).  I booted a Ubuntu 12.10 LiveUSB, used efibootmgr, and found out that Windows 8 (each time it boots) changes EFI default bootloader from Grub to Windows Boot Manager.  How do I change this in Windows 8? I read something about bcdedit, but it does not work or I don't know how to use it...
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I have two systems installed previously Windows 7 and Ubuntu. I was trying to reinstall Ubuntu and format the Ubuntu OS partition using a tool in Windows 7.   When I have Ubuntu ready on a USB stick and restart my laptop, it prompts me with the GRUB rescue screen. If I boot from USB to install Ubuntu, it just hangs.   Anyway, I messed up everything. So my question is how can I boot Windows 7 now?
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I sent this to boot.repair@gmail.com, still no response thought I could get a faster solution here.  I am running Windows 7 64-bit and Ubuntu 12.04 LTS on separate partitions.  The message is sent is:  Boot-Repair URL:    Originally I was unable to access Ubuntu after a windows update (Ubuntu was installed using wubi). Rather than logging into Ubuntu from the Windows 7 Bootloader, it lead to the grub> command prompt.  No matter what I did here, it would not log me into linux.  As a result I uninstalled Ubuntu from the Add/Remove Programs application in Windows 7.  I then re-installed Ubuntu 12.04 LTS using a liveCD-USB.  This time however, I created a partition.  I then restarted and got the GRUB bootloader which loads Ubuntu 12.04 LTS with no problems, however when I select windows (listed as "Windows 7 (loader)"), it just refreshes the grub bootloader instead of loading Windows 7.  I then used the Windows 7 repair disk to run bootrec/fixmbr and bootrec/fixboot.  This led to no bootloader coming up when I started my computer.  Instead I got a blank black screen with a flashing white cursor.  I went on to do a bootrec/buildbcd and bootrec/scanos.  These did nothing to change the situation.  When I ran bootrec/scanos it said that no Windows 7 installations were present.  After this I decided to reinstall WIndows 7 only for this to do nothing to change the situation.  Afterwards I did a boot-repair in which I began to get the GRUB bootloader, which would load ubuntu 12.04 LTS, but still would not load Windows 7.  I also did a sudo update-grub which recognized Windows 7 as being installed, but still didn't fix the issue of loading Windows 7.  While running Ubuntu I have no problem accessing my WIndows 7 partition which is formatted as NTFS.  It shows all the files and folders reflecting that the re-install did take place, and it also shows all of my old applications and folders in the Windows.old folder.  I am completely stuck at this point and have no clue what I should do next.  Any help you can offer me will be greatly appreciate.  Thank You  --gap