I was trying to increase size of /dev/sda1 in VMware workstation, and followed a suggestion to unmount /dev/sda1, becuse of error "device busy".

so i umounted and now i can't boot it.

i get "Operating System not found"

The host is windows 10, guest is Ubuntu 16 (command line, no GUI)

How can i mount back sda1?

Maybe i can boot VMware instance via LiveCD and do something there?

I started from iso and created partition from fdisk so now i can access shell and /dev/sda1 from rescue console.

But original install still doesn't boot.

I marked sda1 as Boot * but it still not boot the guest.

In rescue console i can Reinstall GRUB boot loader. Should i try it or can it destroy data on disk?

  • When you say that you "can't boot it", what exactly does "it" refer to? The host or the guest?
    – user
    Feb 17 '17 at 14:56
  • @MichaelKjörling the guest
    – Mike
    Feb 17 '17 at 15:01

So i did this:

I set up VMware workstation to boot from Ubuntu Server Iso. (DVD/CD settings)
Then (after language choice), there is menu "Rescue the system"

Before unmounting i had 3 partitions: sda1, sda2,sda5.
Sda5 was my swap partition and doing steps below left
drive without it.

I lanuched console, fdisk /dev/sda.
Then in fdisk console:
n (new partition)
1 (first partition)
a (to mark as boot)

I'm not sure if above part was required.

Then i downloaded a Desktop iso of Ubuntu and launched it as Try Ubuntu

Then i installed boot-repair as documented here: https://www.howtogeek.com/114884/how-to-repair-grub2-when-ubuntu-wont-boot/

Then i set back DVD/CD back to detect drive and Vmware system boots up.

Adding swap Since unmounting and mounting like above took all available space i had to create another partition for Swap. I added disk data via Vmware and then followed this instructions https://askubuntu.com/questions/180730/how-do-i-restore-a-swap-partition-i-accidentally-deleted

Additional info
After doing above i couldn't launch back from cd (it booted to drive immediately).

The option is to boot to Bios https://superuser.com/a/940436/664498, and setup launch from CDROM as first, then drive.

  • You should have been able to rescue your system by booting the Ubuntu 16 ISO from the CD-ROM, then recovering your sda1 with testdisk. After that you can move your partition boundaries with gparted and use boot-repair to regenerate the grub data. You would then not need to boot via a CD-ROM image.
    – AFH
    Feb 17 '17 at 20:55

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