Can't install from USB drive

Thank you for taking the time to report this issue and helping to make Ubuntu better. Examining the information you have given us, this does not appear to be a bug report so we are closing it and converting it to a question in the support tracker. We understand the difficulties you are facing, but it is better to raise problems you are having in the support tracker at https://answers.launchpad.net/ubuntu if you are uncertain if they are bugs. You can also find help with your problem in the support forum of your local Ubuntu community http://loco.ubuntu.com/ or asking at https://askubuntu.com or https://ubuntuforums.org. For help on reporting bugs, see https://help.ubuntu.com/community/ReportingBugs.

FYI: You filed your bug report against `ubuntu-release-upgrader` which will change an installation from one release (say 18.04) to the next release (18.10 or 20.04, a tool that isn't involved with installation issues.

Your issue however is user-controlled; either a faulty ISO download (did you verify it?) or bad write to installation media?

This package failure looks like it was caused by a corrupted file system, or device failure. eg. look in the logs and you'll see lots of messages like these :-

[ 304.135089] SQUASHFS error: zlib decompression failed, data probably corrupt
[ 304.135095] SQUASHFS error: Failed to read block 0x38e155a3: -5
[ 304.135096] SQUASHFS error: Unable to read data cache entry [38e155a3]
[ 304.135097] SQUASHFS error: Unable to read page, block 38e155a3, size b71b
[ 304.135100] SQUASHFS error: Unable to read data cache entry [38e155a3]
[ 304.135101] SQUASHFS error: Unable to read page, block 38e155a3, size b71b

Did you verify your ISO? as per instructions (https://tutorials.ubuntu.com/tutorial/tutorial-how-to-verify-ubuntu#0)

or more likely to be an issue in my experience is the write to your installation media; did the verification complete successfully? It may have as I did see

CasperMD5CheckResult: pass

but errors are evident in your logs that, if it was me trying to install a system using your media, would repeat the validation steps

- ie. re-verify your ISO checksum
- re-write to media & perform that check.

If I have issues on one box; I tend to boot the installation media on another box (commonly two, one that is rather similar & one that is very different). If the media verifies successfully on those other boxes; then it's a box specific issue on the machine you're trying to install to. If the media fails on the other box (or boxes) then you have confirmation the ISO or write of ISO to media was faulty.

In my experience the write to thumb-drive media is most at fault; it's cheap media made to cost.

I'd re-verify your ISO, and write again to a different thumb-drive & ensure your write of ISO to media completes successfully. I'll add some links on how to do the write of ISO to media

- https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-ubuntu#1-overview
- https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-macos#1-overview
- https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-windows#1-overview

Note: my scan of bug report was quick & stopped when I saw 52 SQUASHFS errors, which are almost certainly user-issues with media (where ISO & thumb-drive write need verification), of if it's to a VM/virtual machine; user didn't provide enough RAM for VM to operate correctly where both VMWare & Oracle have stated it's user-error at fault & not their software?....).

A Big hat tip and many thank you go out to Lin Ethan. Ubuntu is now loaded and working. How he knew that it was a corrupt USB drive when at initial start the file checking software declared everything good, is beyond me. I would never have thought of it, because everything checked out as OK. There-in lies the bug. Again, many thanks to Lin and everyone who responded.