Why Doesn’t my Bootable USB Boot
@WinEunuuchs2Unix The reason why I added a flowchart to my answer was to give this question a suggestion to add more direction to it. I suppose this flowchart could be expanded and improved, for example by adding UEFI/BIOS and Syslinux groups to it.
@karel I was hoping that you would submit one of your flow charts. It might be a big chore putting every reason on it but it sure would be enlightening.
I’d consider most of this “question” being an answer actually (see What do we do with this question that is really an answer?). I think the complete list should rather be a (community-wiki) answer to a short, generic question than to be spread among the question and multiple answers.
@C.S.Cameron I think we should just reopen this and then you can move your list from the question into a new answer. The other answers can remain. (Or, honestly, it could even mostly stay as it is. You could ask, «Besides the following, what. » But moving your list into its own answer would probably be better.)
3 Answers 3
More reasons not on the original list:
- Bad USB flash drive. This could even be a new flash drive which I assume to be not corrupted. Ubuntu will boot after making the Ubuntu live USB on a different USB flash drive. It’s worth a try if you have two or more USB flash drives.
- Reformat the flash drive and reload the Ubuntu ISO from an application for making a live USB. If your hardware is very old try creating an Ubuntu Minimal USB for Ubuntu 20.04 and earlier.
- Check the Ubuntu ISO that you downloaded against its SHA256 checksum to verify that the checksums match.
- Voltage irregularities that affect the smooth amount of voltage delivered from the motherboard to the USB flash drive. Possible causes of this are motherboard, power supply and even irregular house current. A very old computer is more likely than a new computer to have issues with the motherboard or power supply that affect booting to a live USB session. Here are a few suggestions that worked when I tried them.
- Don’t plug in USB devices like mouse and keyboard next to each other. Plug in one USB device at the front and one at the back. Or unplug the mouse entirely. You can also save power by temporarily disconnecting unused hard drives.
- Disconnect unnecessary devices when booting the USB to reduce the power load, for example disconnect one HDD if there are two drives. If you have a 4-port USB splitter with switches on each port this is ideal, because you can turn the USB mouse off when you don’t need it and you don’t need to open the computer case to disconnect an internal drive in order to reduce the power load.
- The Ubuntu live USB will sometimes be able to boot if the same computer is moved to another location that has a more controlled source of current or connected to an uninterruptible power supply (UPS).
If this was part of a flowchart I would group all of the hardware reasons as child nodes branching out from the same parent hardware node. Similarly I would group the Casper nodes together and the grub nodes together, branching out from a Casper parent node and a grub parent node respectively.
You added a nice flowchart about possible problems with the UEFI/BIOS system, but the text is so small, that it is difficult to read. I have rather new glasses, but it is difficult anyway, even when I enlarge the picture in fullscreen with 1920×1080 resolution. Would it be possible to re-design it, so you can use larger font in each box?
Fullscreen won’t enlarge it as well as clicking anywhere on the image to show it in full size. Yes, it will be possible to redesign it, and it won’t take any extra time to do it because I’m planning on redrawing all the charts eventually anyway. Right now I just want to get some charts posted to illustrate the basic troubleshooting concept, and encourage other users to post more content that will help me to draw the branching and navigation.
@karel: Perhaps a heading for software might be ok to cover applications for making Ubuntu live USBs, Corrupt ISO/MD5SUMs, etc.
Why Doesn’t a Bootable USB Boot
This question is asked often in Ask Ubuntu, sometimes with few hints about the situation. Please provide a list of possible reasons to help troubleshoot the problem.
This is a double post of Why Doesn’t my Bootable USB Boot As this is the better post for the site, I suggest removing the other one to prevent this one being closed as a duplicate. You question has merit but double posts are not allowed.
4 Answers 4
There are many reasons a persistent USB might not boot.
- USB not set as first hard drive in BIOS
- Problems with BIOS or UEFI boot partitions or files.
- Secure Boot is not turned off
- Drive not compatible with computers BIOS or UEFI boot mode
- Incorrect partition table
- Out of date BIOS/UEFI firmware
- Junk in volatile memory
- Fstab entry in Full install USB referring to HDD’s efi boot partition on drives created on uefi machines.
- Incorrect root partition in grub
- Incorrect path to ISO in grub
- Incorrect persistent-path, (if used), in grub
- Grub menu entry structure not suiting OS
- Incorrect file type for vmlinuz and initrd (.efi and .lz)
- The word «persistent» is missing from grub.cfg, txt.cfg, syslinux.cfg or text.cfg
Persistence (casper-rw and home-rw)
- Persistence partition is not an ext filesystem
- Persistence file not on FAT filesystem
- Persistence file/partition reused from different version
- Persistence file full of data, or file update attempted
- Corrupted flash drive, reformat and reload
- Bad flash drive
- Not enough RAM to run Ubuntu
- Bad or incorrect USB socket
- Incompatible computer CPU
- Incompatible computer GPU
- Computer does not meet minimum specs, a lighter version of ‘buntu is required
- Motherboard voltage irregularities
- Motherboard BIOS limitation with multiple USB devices
- Bad MD5SUM / corrupt ISO file
- Modified or corrupted ISO9660 partition
- USB was removed from computer before ISO file is completely copied
- Out of date boot drive creation tool
- User inexperienced with boot procedure
Thanks to karel and sudodus for help with the answer. See Why Doesn’t my Bootable USB Boot
I know from experience that if a GUI USB creator like Rufus or Startup Disk Creator doesn’t work then dd won’t work either for the same (usually hardware-specific) reason. Sometimes it is possible to troubleshoot why a bootable USB doesn’t boot if it is hardware specific (see below screenshots). For example, safe graphics is not working is a clue to an underlying hardware-specific problem. In this case enabling the nomodeset kernel boot option might work. Otherwise it is often possible to circumvent a hardware issue by installing Ubuntu using the lightweight, text-based Ubuntu minimal CD/USB.
More reasons not on the original list:
- Bad USB flash drive. This could even be a new flash drive which I assume to be not corrupted. Ubuntu will boot after making the Ubuntu live USB on a different USB flash drive. It’s worth a try if you have two or more USB flash drives.
- Reformat the flash drive and reload the Ubuntu ISO from an application for making a live USB. If your hardware is very old try creating an Ubuntu Minimal USB for Ubuntu 20.04 and earlier.
- Check the Ubuntu ISO that you downloaded against its SHA256 checksum to verify that the checksums match.
- Voltage irregularities that affect the smooth amount of voltage delivered from the motherboard to the USB flash drive. Possible causes of this are motherboard, power supply and even irregular house current. A very old computer is more likely than a new computer to have issues with the motherboard or power supply that affect booting to a live USB session. Here are a few suggestions that worked when I tried them.
- Don’t plug in USB devices like mouse and keyboard next to each other. Plug in one USB device at the front and one at the back. Or unplug the mouse entirely. You can also save power by temporarily disconnecting unused hard drives.
- Disconnect unnecessary devices when booting the USB to reduce the power load, for example disconnect one HDD if there are two drives. If you have a 4-port USB splitter with switches on each port this is ideal, because you can turn the USB mouse off when you don’t need it and you don’t need to open the computer case to disconnect an internal drive in order to reduce the power load.
- The Ubuntu live USB will sometimes be able to boot if the same computer is moved to another location that has a more controlled source of current or connected to an uninterruptible power supply (UPS).
Xubuntu 16.04 usb flash. При загрузке с usb пишет boot error
Установка Windows XP на USB HDD (USB Flash Drive, Compact Flash, .)
Установка Windows XP на USB HDD (USB Flash Drive, Compact Flash, . ) Кто пробовал, у кого будут.Usb Flash boot — Windows Xp-sp3 для инсталляции На диск С:
Доброе всем утро! Тема не нова, но есть одно НО. Пытаюсь сделать загрузочную флеху с виндой.Соединение usb+usb+usb+usb+flash
Здравствуйте. Возникла проблема. Купил 4 провода usb (M-F) по 5 метров, соединил их что бы получить.Выбором USB Flash / USB HDD, посоветуйте.
Добрый день ув. участники форума. Требуется ваша помощь, желательно только тех кто испытал и то.Была такая же проблема, когда записал флэшку с помощью UltraISO. Хотел поюзать новую Убунту, без установки
Но записывал флэшку на Linux Mint 17.3 Cinammon программой — Unetbootin — и всё запустилось отлично!Сообщение от Dolphin если записываю через Startup disk creator, тогда загрузка меню появляется, но тут же появляется строка boot error, и все останавливается.
если записываю через unetbootin тогда, загрузка вообще не происходит, пишет что-то вроде missing operation system. или missing disk что -то такое.poss, (если еще актуально) — согласно моему опыту, наиболее надежный способ: использование утилиты dd.
Записывал на 3 или 4 флешки около 5 дистрибутивов и всегда работало.
Единственное, перед записью удали разделы на флешке и создай новую карту разделов в GParted.Сообщение от TaiGeddar Dmitry, конечно.
sudo dd if= of=
для того чтобы отобразить прогресс, откройте новую консоль и наберете sudo watch -n 3 killall -USR1 dd
Вроде путь к образу не должен содержать кириллицы, но я всегда запускаю dd из той же папки, где лежит образ, поэтому сказать ничего не могу.
Еще я вспомнил — для создания мультизагрузочной флешки использовал multisystem (вроде так, позже точно скажу и ссылку кину).
С ее помощью записывал ubuntu, debian, arch и kali. Кроме kali все работало отлично. На kali grub ругнулся и я забил.Сообщение от TaiGeddar
Сообщение от Dolphin 
