I am attempting to install a dualboot (Ubuntu on top of Windows 10) to a PC I have just built myself. I have no problem installing Ubuntu, its just I am unable to setup my computer to boot into it afterwards.

During the instalation I am told that the GRUB does not install properly and I also hit errors when trying to run a boot repair program in terminal.

I am creating the installation using Rufus, and making use of the MBR parition scheme. The Disk I am creating it on is GPT, but when I try use this partition scheme in Rufus an error scheme comes up when I try boot this from a USB stick. This is shown in the next image (and note my bios mode is set to UEFI).

enter image description here

For reference my motherboard is a "MSI B450 TOMAHAWK MAX Motherboard ATX".

What is the best course of action to take? I found some videos that showed how to convert my from UEFI to legacy boot and to change my disk to a MSB partition, would this be the best solution or will this create further problems down the line?


3 Answers 3


I'm not an expert, but sounds like you are mixing concepts. If you use mbr system you are using your pc bios, and if you use gpt, you must use uefi system. Mbr is a file system and gpt too. You have to select mbr or gpt in rufus according to what boot system you want to boot from. If you try to install grub on a gpt system when you choose mbr on rufus, the instalation is not going to find the place to put grub files You must change your hdd/ssd file system to mbr if thats the option you are selecting on rufus because linux install is not going to do it. You can change it under windows terminal using diskpart

  • Ok I think you are right there. Do you know if there will be any downsides to that? Or would I be better off trying to get the GPT install to work?
    – Eoin Hanan
    Oct 7, 2020 at 15:43
  • Mbr system only supports four primary partitions. If you want more than these, you have to create an extended partition with children partitions hanged from the extended one. Gpt suports as many partitions as you need/want, but adding new entries to grub created by user is a little bit more difficult. OS entries are created automaticly detecting kernels. You won't have any problem if you just want Linux and windows entries Oct 7, 2020 at 19:50
  • If you install windows in one partition, and Linux with boot, swap, home, temp & var partitions, you necessary have to use gpt. Many people will tell you that this config is not necessary. I think it's something that comes from Linux old days, and more suitable for multiuser servers rather than a home pc Oct 7, 2020 at 20:00
  • But listen to more experienced users opinion, because I'm just a newbie on Linux Oct 7, 2020 at 20:01

Please, spear some time to read some basics about the principal concepts:

The MBR (Master Boot Record) or GPT (GUID Partition Table) are two (but not only ones) partition table types. These occupy some first bytest at the beginig of the disk and contents the information about the organisation of the whole disk. You cannot, of course, mix these types together. MBR has its limit in total disk space (disk capacity =< 2TB), and GPT is recommended to be used with the uEFI boot loader.

Hence, if you insist on use of dual boot, (I do recommend to use Virtual Machine for MS-Windows and Linux as base OS), the step by step install process is following:

  • choose a free disk of sufficient capacity
  • install MS-Windows (use of MS-W10 forces the use of uEFI, GPT, and Windows Boot Manager) and let some (say about 60 GB) free space for the Linux instalation
  • install Linux OS (I recomend the Debian Linux what is in fact the chassis for Ubuntu OS)
  • the installatinon finishes with instalation of GRUB boot loader - its uEFI version, which includes all detected OS into its boot menu

For the Debian instalation you can download the ISO image of the installation CD here and you can either burn this debian-xxx-netinst.iso to CD or copy this image onto USB flash disk (by dd command while running any Live Linux)


Debian is not as friendly user as Ubuntu, and if you have any issue you are not going to find as many solutions as Ubuntu. IMHO Ubuntu has by far much more users than Debian at least in non professional enviroments, but I agree that Ubuntu and Debian are very similar

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