Grub 2 installation failed during 18.04 installation

Question

I was having Ubuntu 16.04 alongside Windows 10 and having dual boot and everything was just fine. I deleted the partition of Ubuntu 16.04 from Disk Management in Windows in order to install 18.04 on it and it just happened during the installation progress.

Now from the Disk Managment there are 5GB used in this partition and I think that 18.04 is installed but I can't access it and my PC boots directly into Windows.

Solution

What you've done is a mistake. But a solution is available.

How come you delete the Ubuntu partition from Windows when you're on a dual boot?

GRUB is the bootloader and it is contained in the partition alongside Ubuntu. GRUB helps you load your Operating System. Without the bootloader, how come you come load the Operating System now?

Solution:

There is absolutely no loss of data from Windows.

You need a bootable DVD/Pendrive containing your version of Windows. Say, you have Windows 10 Pro on your PC, you need a boot Disk/Pendrive containing Windows 10 Pro; If it's Windows 7 Professional, you need a drive containing Windows 7 Professional.

Plug it, restart your PC and enter boot mode. Select Repair Windows... option and open Command Prompt. In the CMD, type the below commands:

1. bootrec.exe /fixboot
2. bootrec.exe /fixmbr

This would fix everything. Years ago, I've come across the same problem.

Now, you can log in into Windows as you did earlier. Go ahead and download Ubuntu 18.04 and dual boot your PC.

Comments

[Apologician]

Will you add the output of sudo lsblk -o name,mountpoint,label,size,fstype,uuid&&sudo fdisk -l to your question?

[WinEunuuchs2Unix]

@L.D.James OP has deleted Ubuntu 16.04 partition Windows 10 so running lsblk is no longer possible.

[Apologician]

@WinEunuuchs2Unix It's was impressive that the user is in the process of trying to reinstall, or recover the installation that he thinks he had done. He'll have to use the Ubuntu tools from the live media for this.

[WinEunuuchs2Unix]

@L.D.James Hopefully you are right about live USB. I had the feeling after deleting Ubuntu 16.04 using Windows 10 and then installing 5GB worth of 18.04 recovery would be impossible. A clean install of 18.04 (or 16.04 if 18.04 has bugs for OP) seems like the painless route.

[Apologician]

@WinEunuuchs2Unix You might be right about the lost. The user is a novice. While he might be giving a perfect assessment of the state of his system, I believe the command line will make things clearer and most certain to many of us.

[WinEunuuchs2Unix]

@L.D.James Your lsblk command is certainly helpful to know in all situations to get an overview of the partitions. For example what if the selected partition was too small? What if it was the wrong file system type?, etc. etc. Any question here can have many good answers depending on the User level and environment.