I can’t download any version of the .iso for 26.04 desktop that passes checksum. I have tried multiple download mirrors, browsers, and devices. Same error “sha256sum: ubuntu-26.04-desktop-amd64.iso: Input/output error”
Relevant System Information:
not even on the device yet. Just the iso file.
Screenshots or Error Messages:
The check:
sha256sum ubuntu-26.04-desktop-amd64.iso
will output sha256sum: ubuntu-26.04-desktop-amd64.iso: Input/output error
What I’ve Tried:
I have tried multiple download mirrors, browsers, and devices.
I am downloading to my Downloads directory which far exceeds the 8GB recommended size. To clarify, my issue is before the ISO even gets to the USB. It fails a checksum
I’d check what file-system you’re trying to store the ISO to, as many cannot store a Ubuntu Desktop ISO, as it’s size is beyond the maximum limits of some older file-systems…
Your downloads directory may have sufficient space, but is the maximum file-size limit (file-system limit) your issue? as will show as an error when maximum file-limit is reached (ie. I/O error when maximum ‘ceiling’ is hit).
The error message indicates that the problem lies with the system trying to read the file.
What happens if you issue this command?
cat ubuntu-26.04-desktop-amd64.iso >/dev/null
Following on from the comment by @guiverc, what file system is on the device where you’ve downloaded the ISO? If it uses FAT16 or FAT32, the file wouldn’t fit (although you should have received an error while downloading).
You could also check for hardware errors. If it’s your internal or a USB hard drive, look at the SMART parameters. For the device, issue this command:
sudo smartctl --health /dev/[device]
E.g., if your internal device is nvme0n1p1, you’d use:
sudo smartctl --health /dev/nvme0n1p1
The last suggestion that I have is to look for errors. Run your sha256sum command again, followed by this command:
sudo dmesg --ctime | tail --lines=50
See if you spot any errors relating to the hard drive.
In addition to the suggested commands above, you can use the following command lines (copy and paste from here into a terminal window)
ls -l ubuntu-26.04-desktop-amd64.iso # ell ess space minus ell, when in the directory that should contain the iso file
lsblk -e7 -o model,name,size,fstype,fsver,label,mountpoints
The options fstype and fsver will tell us about the file systems in your computer.
If you run the command line and ‘copy and paste’ the command itself and its output into a reply here and render it as code with the button </> it will be easy for us to read.
Finally, please tell us which partition/file system, that you tried writing the iso file into.
Thank you for the help. After some thorough investigation prompted by paddylandau, it appears the issue was with my hardware.
I did a test on my SSD and then tried doing some memory tests. I found that the memory test was giving errors on all channels and not isolated to any CPU core. Replacing my motherboard soon.
Nothing is wrong with the ISO. I was able to test it on a different device with the same download and it worked.
Currently replying from Ubuntu 26.04, so it all worked out in the end.