Invalid partition table error on boot – Fixes for Dell, Windows, Ubuntu

Maybe you’re trying to boot your computer, or you are installing a new HDD or SSD and you are experiencing the error ‘Invalid partition table’. This annoying error can keep you from booting into your PC until you solve the problem that the system has when it tries to access the partition table information.

Invalid partition table error message during boot sequence

The solutions listed below include some specific options available to Dell users, because the problem is commonly associated with their machines, as well as some generic options that should work with any manufacturer.

What causes the ‘Invalid partition table’ error?

If the partition table is damaged or cannot be read, the computer will not know the location or identity of the different partitions on the hard drive. This error can be triggered in any of the following cases:

  • BIOS outdated – The partition error is often seen in Dell devices when an SSD is being installed with an outdated BIOS. Update the BIOS to bypass this problem.
  • Multiple partitions active – Only one partition should be marked active on the hard drive. Disable the partition that does not contain the Master Boot Record to solve this issue.
  • Legacy boot mode enabled – Most modern systems operate best using UEFI, if your computer is using Legacy mode or has Secure Boot turned off, this may cause boot errors.
  • Corrupt Master Boot Record – The boot record tells the computer how to access the OS to boot the system.
  • External Drive – If an external drive is connected, the computer may be trying to incorrectly boot from the external drive. This can be remedied by selecting the correct hard drive in the BIOS.

Hard Drive Basics

All of your data, whether it’s pictures, video, documents, or music, is stored using data storage devices called disk drives or hard drives. Hard drives store your information in magnetic fields, with the magnetized and demagnetized areas representing 1 or 0 respectively. This technology has been in use since the 1980s in the earliest personal computers.

Most users don’t need a heavily partitioned drive unless there is a real need to keep different types of media and data separate. But every hard drive will consist of at least one partition and a partition table. A partition is a segment of the hard drive that is separated from the rest. Partitions are useful because it can help organize data and protect separated data in the event a partition is corrupted.

 A partition table contains important information in 16 byte entries, like which is the system partition. For a standard system, the system partition is 64 bytes, for a maximum of four partitions. The partition table is located in the same sector as the Master Boot Record, which is the first sector on the hard drive.

SSD vs HDD

Historically HDD or hard drive disks were standard, but in the last decade SSDs or solid state drives have gained major traction. Many are replacing their older HDDs for new SSDs and most new computers coming with SSDs. In the next few years, HDDs are looking to become completely obsolete.

Solid state drives are flash-memory chips that are connected together and continue to store data on them even when the computer is turned off. These chips are similar to USB storage devices, but because they are faster and store more data, they are more expensive. SSDs read and transfer data 5-10x faster than a hard disk drive, and you’ll notice the difference if you upgrade. During the installation of a new SSD, you may run into the ‘invalid partition table’ error.

Proven solutions to the ‘Invalid partition’ table error for Dell machines

Dell has recognized that this error is a common problem in their computers and laptops. This error may surface if you are making any changes to the hard drive, such as upgrading to an SSD or changing operating systems.

Below you will find step-by-step instructions on solving this error on a Dell machine with some common operating systems.

Update the BIOS

The BIOS is located on your motherboard and is responsible for providing instructions to your computer for booting into your operating system. The ‘Invalid partition table’ error may be occurring because your BIOS is outdated and therefore not working as intende

If you are using a Dell system, whether you have Windows 10 or Ubuntu, you’ll want to use the Dell Diagnostic Deployment Package which is a tool developed by Dell to create a bootable USB Flash Drive.

dell diagnostic deployment package

Dell has a great support video to help you follow along.

You will need a separate system from the PC you are trying to troubleshoot, to create this flash drive. Once the USB drive is created:

  1. Navigate to Dell’s Drivers and Downloads website to find an updated BIOS version. If your computer won’t boot, you can look at the Dell service tag on the bottom of a laptop or the back of your desktop, to find a Service Tag number, Dell EMC Product ID, or Model number.
  2. Select the BIOS category and find the latest BIOS version for your computer and then click Download File, followed by the single-file download option. Write down the name of the file you saved and the letter of the bootable drive, as you may need it later.
  3. Make sure to save the updated BIOS version onto your bootable USB.
  4. You can now remove the USB from your secondary system and insert into your computer that won’t boot.
  5. Start your computer and press F12 several times during boot to open the Boot Device menu.
  6. Select your bootable USB device from the device list and press Enter.
  7. The BIOS file should automatically open and begin installing. If it isn’t in the command prompt, enter the USB device letter (for example E:\) followed by the name of the file (for example M5600B07.exe) and press Enter.
  8. Once the installation is complete, your system will restart so you can continue using that drive or installing your chosen OS.

Enable UEFI and Disable Legacy Mode

If you are running a Dell computer with Ubuntu or Windows 10, there are a few other things to try to solve the partition problems. UEFI stands for Unified Extensible Firmware Interface and replaces the BIOS by keeping all of that boot data in an .EFI file instead of stored on the firmware. Most modern computers are automatically set to use UEFI. If yours is using the BIOS, it’s a pretty quick fix:

  1. Restart your computer and select F12 during the startup process to open the boot menu. You should see the message, preparing one-time boot menu, in the top right-hand corner. The next screen you see will be the BIOS.
  2. Boot mode should be listed. If your boot mode is set to LEGACY EXTERNAL DEVICES; Secure Boot: OFF or UEFI; Secure Boot: OFF, you will need to continue with the following steps. If your boot mode is set to UEFI; Secure Boot: ON, your system is already correctly configured and you can try another solution.
boot mode set to Legacy external devices
  1. Use the arrow keys to move down to BIOS Setup under OTHER OPTIONS.
  2. Skip this step if you are already in UEFI mode, but Secure Boot is OFF. If your system is using Legacy devices, navigate to General and then Boot Sequence. You can do this using your mouse. Select UEFI under the Boot List Option heading. Click apply and then OK in the pop-up window.
Change boot list option on dell
  1. Select Exit and your computer will restart. You need to navigate back to the BIOS Setup by following steps 1-3.
  2. Navigate to General and then Advanced Boot Options and make sure Enable Legacy Option ROMs is unchecked. Click Apply.
disable Legacy option ROMs
  1. Again on the left-side, navigate to Secure Boot and then Secure Boot Enable. Make sure the Secure Boot Enable box is checked. Click Apply and then Exit.
enable secure boot
  1. Your computer will reboot and if the ‘Invalid partition table’ problem is solved, it should boot normally.

Additional fixes for all device brands to troubleshoot the ‘Invalid partition table’ error

While the first two solutions were specifically aimed at Dell computers, the following fixes can be applied to all device brands – including Dell in case the invalid partition table error is still not resolved.

Disconnect External Drives

This solution is extremely simple, but commonly the cause of this error. If you have an external hard drive, perhaps where you store a backup of all your files, it may be causing this problem. When another hard drive is connected, your computer may inadvertently become ‘confused’.

As the computer starts, the boot order usually tells the system which hard drive to boot into first. If the boot order is wrong, the computer will try to boot into your external drive. Your external drive does not have an operating system, and the ‘Invalid partition table’ error will flag. To fix this problem simply disconnect your external hard drive and restart your computer.

Check and Fix Active Partitions

If your computer uses Windows 10, you can use a Microsoft tool called Diskpart to change which partition is active. Your computer should only have one partition active, this is the partition that the computer will use to boot from. If two are active, the ‘Invalid partition table’ error pops up because the system can’t decide which one to use.

You will either need your original Windows install disk that came with your computer or you will need to create it. If your computer doesn’t have a CD drive, you’ll need to put the installation media on a USB flash drive with at least 8GB of space. Navigate to the Windows 10 installation media site and download the tool. Follow the instructions at the bottom of the page under the tag ‘Using the tool to create installation media’ to complete this process. This will need to be done using a secondary computer.

Once you have your Windows 10 installation media USB device:

  1. Turn your computer off and plug in the Windows 10 installation media. Restart and select F12, F2, Delete, or Esc (depending on the manufacturer) if the PC does not automatically boot using the USB device. This will open the boot menu.
  2. Select your language, timezone, and keyboard input, then click Repair your computer.
  3. Click the correct installation drive, which is generally C:\ and then select Next.
  4. System Recovery Options should appear, here you will select Command Prompt.
  5. Now we want to select and mark the non-operating system drive, as inactive. In the command prompt, write “diskpart” and press Enter.
  6. Now type “list volume” and press Enter. If you have two active partitions, you will see two drives with an asterisk(*).
  7. Your operating system should be on drive C:\, so you want to select the other drive so you can inactive it. Now type “select volume [X]“. Replace the [X] with the volume number that corresponds with the non-operating system drive. Press Enter.
  8. Write “inactive” to mark that drive as inactive and press Enter.
  9. You are now able to restart your system to see the ‘Invalid partition table’ error disappears.
using diskpart tool to fix active partition

Note: If you can’t create an installation media, Windows 10 has a new feature to allow you to enter the repair menu without it. If your computer doesn’t automatically recognize there is an error upon boot and enter the Automatic Repair menu, hard reset your computer by pressing the power button. Do this as soon as the blue Windows logo appears. You will need to restart and do this 2 or 3 times. This will force your computer into the repair menu. Once you are in the repair menu, you can select Command Prompt and continue checking and fixing the active partition as detailed above.

Rebuild the Master Boot Record

If your Master Boot Record is corrupted, your computer will not be able to boot at all until this is fixed. Windows 10 has a tool, the Recovery Console, that can be used to fix the Master Boot Record. The Master Boot Record can be damaged by malware, so it’s important to keep your system free of any malicious software.

Here is how to rebuild the Master Boot Record:

  1. Insert your Windows installation media created in the last solution and Restart your computer. Your computer should automatically boot using the installation media. If it doesn’t, restart your computer and select F12, F2, Delete, or Esc to boot into the boot menu and select the drive that corresponds to the installation media.
  2. Once the system boots using the installation media, click Repair your computer.
  3. In the Automatic Repair window select Advanced options.
  4. In the Choose an option window select Troubleshoot. Select Advanced Options again.
Windows automatic repair
  1. Now in the Advanced options window select Command Prompt.
  1. In the command prompt window, type “bootrec.exe /fixmbr” and press Enter. This will run the Bootrec program and recover the MBR.
  1. When the command prompt is finished running the commands and you see the message ‘The operation completed successfully’, you can restart your computer to see if the problem is fixed.

‘Invalid partition table’ error solved

This problem is most commonly associated with Dell machines, which is extremely evident from the search results when trying to find a solution to this problem. It’s possible your external hard drive was interfering with your boot order, and thankfully that’s a very simple fix.

Your BIOS may have been outdated. While this is not a very common problem, an outdated BIOS may be triggering compatibility or boot errors. Thankfully for Dell users, Dell has created a tool and guide to fix this outdated BIOS problem. Dell users can also quickly adjust their boot mode, from Legacy to UEFI Secure Boot. Maybe you had two partitions active and needed to disable one, or your MBR was corrupt. In any case, the problem should now be solved.

If none of these solutions worked, your hard drive may be failing. There could be bad sectors on your hard drive, and if the partition table or MBR sector is damaged this could be triggering the ‘Invalid partition table’ error. Try to either replace the hard disk if you have a spare, or contact an IT support professional to further troubleshoot your device.

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