Comment 62 for bug 1766945

Hello,

Here's my experience this issue and the solution which worked for me (though, it would be great if someone would resolve it in a more straight-forward matter):

Needed to convert a Windows 7 Ultimate machine to a dual-boot with ubuntu 18.04.3.
The machine was set based on legacy bios, Windows 7 Ultimate installed on an MBR disk, while there was a second (physical) HD for data, formatted as GPT.
Booting ubuntu bootable USB, it did so as UEFI.

1.
Used ubuntu to create a bootable USB (using the default "Startup Disc Creator").
Made some space on the OS HD for /root, and some more on the DATA HD for /home.
Then encountered the "No EFI system partition was found, the system will likely not be able to boot successfully and the installation may fail", which indeed reported failure.

2.
Upon reboot, Windows started with no grub menu.
Then using the same bootable USB, installed [Boot-Repair](https://help.ubuntu.com/community/Boot-Repair) and followed the instructions. Some of the commands resulted in errors, yet GRUB was installed successfully. Boot-Repair generated the following report: http://paste.ubuntu.com/p/c3f9zHjzfq/

3.
Then GRUB did not show up and ubuntu started.
Following ["Dual boot pc boots directly to ubuntu instead of showing grub menu"] (https://askubuntu.com/a/750123/44517)

verified grub was installed using:
`grub-install --version`

edit grub to comment out (add "#") to the line including: "hidden"
`sudo -H gedit /etc/default/grub`

resulting in it now reading:
# GRUB_TIMEOUT_STYLE=hidden

And updating grub:
`sudo update-grub`

Now the system is up and running, starting with a GRUB menu allowing to choose between ubuntu and Win7 .

Found on the web another solution, which I did not try:
It was suggested that deleting the "efi" folder from the bootable USB would allow an ubuntu installation alongside the windows one, in legacy bios mode, without issues.