Ubuntu 18.04 ISO downloaded2019-02-16 Failed to remove a part of itself,

[L. P. Luigi Espenlaub]

file:///var/log/syslog
file:///var/log/partman
file:///var/log/installer/debug
file:///var/log/installer/version

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.12
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CasperVersion: 1.394
Date: Sun Feb 17 02:37:32 2019
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd quiet splash --- maybe-ubiquity
LiveMediaBuild: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Foundations Team Bug Bot (crichton)]

Exception during installation:
Feb 17 07:36:45 ubuntu /plugininstall.py: Traceback (most recent call last):
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1725, in <module>
Feb 17 07:36:45 ubuntu /plugininstall.py: install.run()
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 61, in wrapper
Feb 17 07:36:45 ubuntu /plugininstall.py: func(self)
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 239, in run
Feb 17 07:36:45 ubuntu /plugininstall.py: self.remove_extras()
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1445, in remove_extras
Feb 17 07:36:45 ubuntu /plugininstall.py: self.do_remove(recursive, recursive=True)
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1028, in do_remove
Feb 17 07:36:45 ubuntu /plugininstall.py: install_misc.chroot_setup(self.target)
Feb 17 07:36:45 ubuntu /plugininstall.py: File "/usr/lib/ubiquity/ubiquity/install_misc.py", line 128, in chroot_setup
Feb 17 07:36:45 ubuntu /plugininstall.py: with open(policy_rc_d, 'w') as f:
Feb 17 07:36:45 ubuntu /plugininstall.py: FileNotFoundError: [Errno 2] No such file or directory: '/target/usr/sbin/policy-rc.d'
Feb 17 07:36:45 ubuntu /plugininstall.py:

[L. P. Luigi Espenlaub (luigiwriter2)]

Went to
https://tutorials.ubuntu.com/tutorial/tutorial-how-to-verify-ubuntu#3
to check the ISO check-sum to see if the download was corrupted
or if
I had burned it to a faulty DVD.
However I could find no workable answer to this question.

how to download SHA256SUMS from http://releases.ubuntu.com/bionic/?

Seems the most simple question, however all I get at Ask.Ubuntu, stack exchange and gethub is theory others problems and complications.

 http://releases.ubuntu.com/bionic/ does not offer a copy or download option for the files.
Other click on the file and all I get in Firefox is link choices. I have been warned in one of those sources that copying and pasting contents into a file I create will fowl up the process.

Not being able to successfully download the SHA256SUMS means I only receive the following when attempting to confirm validity of the ISO

gpg: can't open `SHA256SUMS.gpg'
gpg: verify signatures failed: file open error

All I can do is possibly waste another DVD downloading a valid? ISO with a bug in it, in doing a new download, but that is the only course I see for now with the gpg check-sums kerfuffle at:

https://github.com/canonical-websites/tutorials.ubuntu.com/issues/new
and
https://github.com/canonical-websites/tutorials.ubuntu.com/issues/790

Will update with the results of a new ISO and DVD install.

[L. P. Luigi Espenlaub (luigiwriter2)]

The Bug is having diskparted fail to report it had encountered a DOS partition table with a hidden DOS partition that it could not re-partition or completely re-format. I only found this out by running the Ubuntu recovery option after the install fail and the subsequent boot failure. This would have saved me several weeks. [first try was Ubuntu 14.04 LTS] **See 2019-02-22 comment.