grub fails to install during fresh install on a side partition

[William Main]

USB install aside of 16.04 is second (divided) partition, all ok but fails to install grub. Tried all 3 choices sda6 (usb, which boot fine BTW), 16.04, and some strange windows version, all fail equally.

Looks like a write problem like maybe it out grew expected space when stored

device is Lenevo ideaPad with Intel core i7 8GB ram, 1 terabyte HDD 2.5m cache, using amd64 download retrieved yesterday July 8

note 18.04 runs fine off the USB and 16.04 still boots (though it is no longer usable since an auto update cause the default key ring system to so relentlessly request a password that locks the screen while it waits so nothing else can be done at least from a keyboard) 16.04 ran fine for year till the update 2 or 3 weeks ago now) Just as an aside I never yet found out how to set the default key ring password. nothing I have seen on the web is current enough to be useful.

Tried this now several times. have take the time using the USB running version to mount the the 16.04 partition and copy the /home space to a terabyte usb drive so I can now step on the primary partition.

and try installing there. if that fails it will speak volumes.
Hope this helps

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CasperVersion: 1.394
Date: Mon Jul 9 14:56:48 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[William Main (william-main)]

just thank you for the efforts you folks put in on this great product!

[William Main (william-main)]

tried 18.04 over the top of successful booting 16.04 with exactly same failure result so it is not where it is trying to place it.

I am attaching a screen shot of the failure.

[Phillip Susi (psusi)]

Your disk is currently partitioned to boot in bios mode, but you booted the installer in EFI mode. You either need to boot the installer in bios mode, or partition the disk using GPT and set up an EFI system partition to install in EFI mode. This will be done for you if you choose the "use entire disk" guided install option.

[Steve Langasek (vorlon)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1766945, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.