So I've read newer computers who ship with windows 8 and 10 are using UEFI. I want to dual boot Windows 10 and Ubuntu, I'm using a computer with Windows 10 installed but it originally had Windows 7, is it probably running UEFI? How do I find out if my OS is installed in UEFI mode?

  • This is clearly a Windows question, however UEFI uses the GUID Partition Table which Ubuntu fdisk will complain about and ask you to use gdisk instead. This may provide some clues – Elder Geek Oct 17 '15 at 17:43
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    Only a few Windows 7 systems were installed with UEFI, most are BIOS with MBR partitioning. If you have MBR then Windows 10 will be BIOS boot also as Windows only boots in BIOS mode from MBR or only in UEFI mode from gpt partitioning. It will not convert how you boot currently even if hardware is UEFI capable. Post this from Ubuntu live installer to see partitioning: sudo parted -l Most Windows 7 systems also used all 4 primary partition in MBR. askubuntu.com/questions/149821/… – oldfred Oct 17 '15 at 18:25

I got a laptop which has pre-installed Windows 8.1 and I am now using Ubuntu 14.04 with Windows 8.1 in dual boot mode.

If you are going to install Ubuntu 14.04 , I will say it is prefereable to install Ubuntu in (U)EFI mode because of problems specified in this thread.

You can find out which Boot mode you are using from these articles.

article1 article2 article3

If you still have doubt and open BIOS and find out which entries are listed in (U)EFI mode and legacy mode. UEFI mode: UEFI boot mode

Legacy mode (option 3 is for windows OS): Legacy mode


Yes, you should install in UEFI mode because of many advantages of it.

  1. Better security by helping to protect the pre-startup—or pre-boot—process against bootkit attacks. UEFI supports Secure Boot, a useful security feature that prevents malware from hijacking Windows or another installed operating system. Windows supports secure boot, but Linux machines are on their way to support secure boot too
  2. Faster startup times and resuming from hibernation.
  3. Support for drives larger than 2.2 terabytes (TB).

First and most important for a desktop user is UEFI provides with GPT partition table which is better than older MBR. It allows you to make any practically any number of partitions where primary or extended.

MBR works with disks up to 2 TB in size, but it can’t handle disks with more than 2 TB of space. MBR also only supports up to four primary partitions — if you want more, you have to make one of your primary partitions an “extended partition” and create logical partitions inside it. This is a silly little hack and shouldn’t be necessary.

  1. Support for modern, 64-bit firmware device drivers that the system can use to address more than 17.2 billion gigabytes (GB) of memory during startup.

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