Error message question: error: file '/boot/' not found

[darrylandrowan]

Hi,

When I boot Kubuntu 22.04 from my bootable USB on my Dell OptiPlex 7060 SFF PC, I get the error message: error: file '/boot/' not found just before it enters the GNU Grub version 2.06 screen/menu. It happens very quickly, but I am curious on what it is and why it occurs. Everything seems to work well otherwise. I created the bootable USB using Disks - Restore Disk Image tool.

Any information would be helpful.

Regards,
Darryl

[claydoh]

I created the bootable USB using Disks - Restore Disk Image tool.

Not sure what this tool (Gnome?) uses to 'burn' the image, but generally, messages like this are more like leakages of irrelevant information, if it boots correctly. it is not unusual or worrisome, unless there was a problem.
My guess is that whatever it has set up is looking for different types of boot files, and was going through various options before finding the one that works.

[darrylandrowan]

Thanks for your reply.

There is no problem with the Live Boot or Install, but I am curious on why the error message appears. I'm only fairly new to Linux based systems and still learning. Any error message to me at this stage is a concern. If I know why it shows and what it's about, it can display all it wants - at least I feel comfortable knowing it's a normal thing and is safe.

I have done further testing and identified that the error message appears with bootable USBs from Linux Mint 21.1 and Ubuntu Studio 22.04.2 as well. Could it be a Dell hardware thing or something to do with boot setup in the BIOS?

Additionally, when I create a bootable Linux Kubuntu USB or Linux Mint USB with Rufus on Windows (using ISO image mode - the recommended option), the message does not appear when booting the USB. However, when I create the Bootable USB using Rufus (using DD image mode), the message appears when booting.

I have done several more tests writing a bootable USB disk in Kubuntu and Mint. I have used "Startup DIsk Creator" and "Disks" (in Kubuntu) and "USB Image Writer" and "Disks" (in Mint). I have also tried using Balena Etcher in the Linux environment. All the options used in my tests show the error message on boot. The only time it did not show is when I used Rufus (Windows) and selected the ISO image mode.

I'm not sure if this information helps to get me a better explaination on why this error message occurs. Perhaps it is the way the ISO is written to the USB.

What are your thoughts?

Regards,
Darryl

[claydoh]

As I said, whatever boot method is used or set up by the software can vary. Some do their own things for booting the image, not using the one native to the image. Sometimes, these informational messages "leak" instead of being hidden, which would be thew norm.

You will likely see this sort of thing regularly. Note that all of yours that show it are Ubuntu, or derivatives and variants. This is a cosmetic 'bug' that is not uncommon. I don't see this one, but I see others sometimes. I doubt it is something wrong in your BIOS, but it could report something there that it is looking for, but is not present on your particular computer. Other distros may not have these, or may have different things leak.

I always see messages about SGX being disabled, even though this is not a bug in any way, or any sort of error. But some developer somewhere, possibly unrelated to the distro at all, marked this as important enough to leak into the visible messaging instead of being hidden. One can modify things to hide *all* messaging, or more of it during boot, but it isn't straightforward on a live session.


My take is that the process is looking for any of a number of files in a list that can be used to boot from, and goes through them until it works.

This sort of thing is a normal 'Linuxy' thing, with lots and lots of information and data available, though most of it is useless and meaningless for 99.9% of uses, and users.

[Schwarzer Kater]

[…] Perhaps it is the way the ISO is written to the USB.
What are your thoughts?

Exactly. Could be.
Perhaps this also has something to do with your UEFI/BIOS… Perhaps it has not.

Imagine a program that checks your refrigerator's contents for whiskeys and opens the refrigerator afterwards if there is any (you have Scotch in your refrigerator):

• if used one way it scans for all possible whiskeys, tells you "error - no Bourbon detected" (because you only have Scotch) and opens the refrigerator - but as Scotch is whiskey consequently the error is irrelevant, so the refrigerator is open and everything is fine
• if used another way it scans if there is whiskey at all, tells you no error (because you have Scotch) and opens the refrigerator - so the refrigerator is open and everything is fine

If you really want to know in detail why this is happening with GRUB (?) or /boot/ you will probably have to screen the concerned code yourself, contact different developers or write bug reports.

But like claydoh already said: this is nothing to be concerned about at all if everything works (for you)…
Diving into the code or pursuing this any further would be quite a waste of time and energy IMHO.