Windows Update Killed My Dual Boot

Hello - relatively new to Linux, been running Zorin for several months now flawlessly … until yesterday … I have Zorin on a partition w/Windows 10 and the dualboot option at startup. The other day Windows 10 updated and now the dual boot menu is gone and I go straight to Windows on restarts and after shut downs … is there a way to either: a) Reset the dual boot menu at restart or after shutdown, b) reinstall Zorin without losing the data I have stored in that environment, or b) login to Zorin from Windows (using a command prompt or something like that)?

I’ve tried a couple of things I’ve found online from what seem like similar issues, but without success … I did make it to the boot sequence menu in UEFI, but had no idea what I was looking at (I saw the hard “drives” and Windows, but nothing that looked like Zorin). From what I can tell, though, the partition is still intact. Many thanks for any help one may be able to provide.

Hello @DVDC
When Windows updates, it often overwrites the boot configuration, particularly the bootloader, making GRUB (the bootloader used by Zorin and many other Linux distributions) inaccessible. This is a common issue, but fortunately, it’s recoverable. Here’s how you can tackle the situation:

  1. Reinstalling GRUB from a Live USB:

    a. Boot from a Zorin OS Live USB (or any other Ubuntu-based distribution’s Live USB).

    b. Open a terminal.

    c. Identify your Zorin OS partition:

    ```bash
    sudo fdisk -l
    ```
    
    You'll likely see a partition formatted as ext4. This is probably your Zorin partition. Take note of its name, e.g., `/dev/sda5`.
    

    d. Mount the Zorin partition:

    ```bash
    sudo mount /dev/sda5 /mnt
    ```
    
    Replace `/dev/sda5` with your partition name if it's different.
    

    e. Reinstall GRUB:

    ```bash
    sudo grub-install --root-directory=/mnt /dev/sda
    ```
    
    Here, `/dev/sda` refers to the entire disk, not just the Zorin partition.
    

    f. Reboot your system. The GRUB menu should now appear, giving you the option to boot into Zorin OS or Windows.

  2. Reinstalling Zorin without Losing Data:

    If the above step fails and you want to reinstall Zorin:

    a. Back up all essential data first, if possible, from a Live USB environment using tools like GParted or Nautilus.

    b. During the installation of Zorin, choose the “Something else” option when you’re at the partitioning step.

    c. Select the partition where Zorin is currently installed, and set it to use the ext4 filesystem. Ensure you set the mount point as /. Do not format the partition if you want to retain your data.

    d. Proceed with the installation. This method will reinstall Zorin on the same partition without formatting, so your personal files will be retained. However, applications will have to be reinstalled.

  3. Accessing Zorin Data from Windows:

    You can’t directly boot Zorin from within Windows using a command prompt. However, you can access Zorin’s files using tools that allow Windows to read ext4 partitions. An example of such a tool is Ext2Fsd. Once installed, you can access and backup your Zorin data from Windows.

Remember, always backup important data before making significant changes to partitions or the OS.