Linux

How to Fix Your Ubuntu Linux PC When It Won’t Boot

Christian Cawley Updated 03-12-2019

You’re booting up, preparing to do some work, edit a document, mix a composition, or just play a game… but something goes wrong.

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Ubuntu won’t boot.

Sadly, as reliable as Linux is in general, and as popular as Ubuntu is, sometimes it runs into problems, just like Windows 10 or macOS. In most cases, you’ll be able to work around this. Here’s how to fix Ubuntu booting problems.

Ubuntu Not Booting? Try These 5 Tips

Ubuntu typically works out of the box. But when problems booting arise, Ubuntu probably takes a while or simply does not boot at all.

If Ubuntu is not starting, work through these five steps:

  1. Check for bootable devices
  2. Is the GRUB bootloader working?
  3. Repair the bootloader menu
  4. Reinstall Ubuntu
  5. Replace faulty hardware

While these steps are designed for Ubuntu users, they can be applied to other Linux operating systems. Note, however, that if you’re using disk encryption, some of these fixes will not work.

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If your Ubuntu system isn’t booting, it’s time to work through these five steps.

1. Is a Bootable Device Causing Ubuntu Boot Problems?

If your computer isn’t booting, could it be because there is a bootable disk attached or loaded?

You’re not alone. One of the most common problems with Ubuntu not booting occurs right after installation. This is because the Ubuntu boot disk (USB device or a DVD) is set as the boot device.

In short, Ubuntu won’t boot after install because the disk is still present. So, eject the disk, and ensure the correct boot device is selected.

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Checking the boot device can be done in your system UEFI/BIOS, or if available, the boot order menu. Both can be accessed from the POST screen, which appears when your PC powers up. Take a moment to change the boot order How to Change the Boot Order on Your PC (So You Can Boot From USB) Learn how to change the boot order of your computer. It's important for troubleshooting issues and tweaking settings, and it's a lot easier than you think. Read More , then try rebooting.

(If you run into trouble finding the boot order menu, check the computer’s (or motherboard’s) documentation.)

2. GRUB Bootloader Issues Might Stop Ubuntu Booting

GRUB is the bootloader that ensures the selected operating system boots. On a dual booting machine, it will list and boot all installed operating systems, including Windows.

However, installing Windows alongside Ubuntu can lead to the bootloader being overwritten, leading to problems booting Ubuntu.

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Other issues can corrupt the bootloader, such as a failed upgrade, or power failure. It isn’t unusual for a bug to ruin the Linux experience 6 Reasons Your Favorite Linux OS Is Plagued by Bugs You found a new Linux operating system to try, and you loved it. But then it went wrong. Sometimes Linux gets buggy after a month or two. The question is, why? Read More .

To check the GRUB bootloader, restart your PC, while holding Shift. You should now see a list of the installed operating systems; navigate the menu using the arrow keys.

Check the GRUB bootloader is Ubuntu won't boot

If not, then the problem is that the GRUB bootloader is broken or overwritten. Repairing the bootloader is the only solution. (If you’re dual booting, you’ll still be able to access Windows).

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Note: If you see the GRUB Bootloader, skip down to the next section.

Repair the GRUB Bootloader to Boot Ubuntu

If GRUB is not loading, then Ubuntu won’t boot. Fortunately, you can repair GRUB using the Ubuntu installation media. Restart the computer with the disc inserted and wait for it to load up.

Again, you may need to change the boot order, as described above. Make a note of the boot order before you change it!

With the installation disc booted into the Live environment, confirm you have a network connection and then open a Terminal. Enter:

sudo apt-add-repository ppa:yannubuntu/boot-repair

sudo apt update

sudo apt install -y boot-repair

boot-repair

This will install the boot-repair tool and run it after the final instruction. Wait for the system to be scanned, then select Recommended Repair. (There is also an Advanced options view, where you can select a default OS, default disk or partition, and more.)

Click Apply when done. You should now be able to restart your PC and boot into Ubuntu. Alternatively, it will be listed an option in the GRUB bootloader menu.

3. Ubuntu Still Won’t Boot? Fix the GRUB Bootloader Menu

If you can see the bootloader, then you don’t have to do any of the above. There is a built-in recovery tool which you can use to help fix Ubuntu booting problems.

In the bootloader menu, select Advanced options for Ubuntu. Next, use the arrow keys to select the entry appended with (recovery mode). Tap Enter to continue and wait as Ubuntu is booted into a slimmed down version.

Use the recovering menu to fix problems if Ubuntu won't start

(If you’ve ever booted Windows Safe Mode, this is similar.)

Several repair options can solve situations when Ubuntu won’t boot. The three you should try, in order, are:

  1. fsck: This is the file system check tool, which scans the hard disk drive and repairs any errors it finds.
  2. clean: Use this to make free space, useful if the reason for Ubuntu not booting is a lack of HDD space.
  3. dpkg: With this, you can repair broken software packages. Failed software installations or updates can cause problems with Ubuntu not starting. Repairing them should solve this.

If Ubuntu has never booted previously, you should also try the failsafeX tool. Graphics drivers or a problem with the Xorg graphical server might be the fault if Ubuntu won’t boot after installing. Use failsafeX to overcome this.

Note that the root menu item is for advanced users who have the skills to fix the problem manually.

4. Ubuntu Not Starting? Time to Reinstall

If Ubuntu won't boot up, take the time to reinstall it.

In the event of a dreadful failure that could prove time-consuming to resolve, you might prefer to simply reinstall Ubuntu. This can be done without overwriting your existing files and folders. In fact, it’s one of the easiest fixes if Ubuntu won’t boot.

Again, boot into the Live environment on your Ubuntu CD/DVD or USB drive, and begin the installation. The installer will detect the existing instance of Ubuntu and give you the option to Reinstall Ubuntu.

Look for the option with the note “Documents, music, and other personal files will be kept…” In most cases, installed software will be retained too.

Of course, as a precaution, you should already have a backup of all your Ubuntu data. This might have been made manually with a backup utility, or using a disk cloning tool like dd How to Easily Clone and Restore a Linux Disk Image With dd If you want to wipe, backup, or restore data on Linux, there are a number of apps you can pick. But whichever Linux operating system you run, there's one command that always works -- dd. Read More . You might prefer syncing data to the cloud via Dropbox or an open source cloud solution. 10 Cloud Solutions You Should Be Using on Linux Some mainstream cloud storage options don't offer a decent Linux client. But you're not out of luck. Many popular services do work under Linux. You can even roll out your own cloud solution! Read More

Once the reinstallation is complete, Ubuntu should be back up and running.

Note: The Erase Ubuntu and Install option is not advised unless other options fail and your data is backed up.

5. Replace Your Faulty Hardware

If Ubuntu won't boot, it may be a problem with your HDD
Image Credit: William Warby

Another cause of Ubuntu being unable to boot comes in the shape of faulty hardware. Boot problems can be caused by:

  • Hard disk drive and cabling
  • Motherboard
  • Processor (CPU)
  • Power Supply Unit

Try our guide for diagnosing a hard disk drive How to Repair a Dead Hard Disk Drive to Recover Data If your hard disk drive has failed, this guide will help you with the hard disk drive's repair and data recovery. Read More . You might also read up on focusing your efforts to diagnose hardware issues that prevent the computer from booting, and repairing them without breaking the bank 7 Tips to Save Money on PC Repairs Need to fix your PC but don't have enough money? Here's how to make simple PC repairs that save money on PC repair shop prices. Read More .

Once a faulty HDD is replaced, you’ll typically need to reinstall Ubuntu from scratch. (Unless you had previously made full disc image backup, in which case this could be restored.)

It’s a scorched earth approach, but will solve problems with Ubuntu not starting.

Say Goodbye to Ubuntu Booting Problems!

If Ubuntu won’t boot, it isn’t necessarily going to be easy to get things running again. If the GRUB bootloader cannot be repaired, it could be a long time before you have a usable computer again. Yet another argument in favor of maintaining regular backups, or at least syncing your valuable data with the cloud!

Remember, this can happen with any operating system, not just Ubuntu. Having doubts? Here’s a quick reminder as to why you should stick with Ubuntu 8 Reasons Why You Should Stick With Ubuntu Linux Use Ubuntu and feel like the developers are losing interest? Here are several reasons to stick with Ubuntu as a Linux user. Read More .

Related topics: Dual Boot, GRUB Bootloader, Linux, Ubuntu.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. raul
    March 25, 2019 at 9:09 pm

    seems this utility is useless if you have an encrypted disk. An encrypted disk with boot issues may be mountable in the Live CD but it'll report as unmountable. Then the Boot repair defaults to this. And then there is an issue with it not being able to connect to the internet in the repair mode yet it seems to upload to the pastebin just fine.

    • Jim
      November 21, 2019 at 12:10 pm

      It still comes down to one thing, back up, back up, back up.........

  2. Roshan Mani
    March 9, 2019 at 3:46 pm

    The initial steps might work only if the disk was *not encrypted*. There seems to be no easy option if encryption was enabled. A full reinstall might be the least painful solution.

  3. Roshan Mani
    March 9, 2019 at 3:44 pm

    The initial steps are suitable only if the disk was *not encrypted*. There seem to be no easy way if encryption was enabled. A full reinstall seems like the least painful solution.

  4. Wimpie
    January 20, 2019 at 7:31 am

    I just want to say to who write this helpful articile. It works perfectly after I repair boot from live ubuntu. Big thanks! Kudos

  5. Rahul Singh
    August 23, 2018 at 8:05 am

    Hi
    My Problems is after succesfully installing Ubantu 16.04 LTS Version when i am clicking resart now then booting is not working he showing no bootloder found what i do plz help?

  6. Vijay Kumar Kanta
    March 20, 2018 at 3:27 am

    I'm using the age old 12.04 due to pc speed issue and it keeps failing to boot. Sometimes I swap had cable or slot or even zer fill. It works after that but again begins to taunt me.

    Finally I assume it's the case where the mobile sits as front USB sometimes won't work and psu makes grin ding sound. Time to change either case or psu or both.

  7. Adarsh kumar
    October 17, 2017 at 10:44 am

    I am not able to recover my ubuntu , I have used boot-repair tool and getting the error "LOCKED ESP DETECTED " .I have no idea what is going wrong .
    Here is the full output of boot-repair command from the live ubuntu session.please have a look.
    https://www.dropbox.com/s/qevq7sp9333a0ay/boot_info.txt?dl=0

  8. Vladimir
    April 16, 2017 at 9:12 am

    Great article. Boot repair is great and easy to use software. I used boot repair a lot, and always solve problem. If using dual boot OS, Win and Ubuntu, in case that some of them have to be reinstalled, some overwriting usually happen and then boot repair solve problem in a minute.