3

I try to install Ubuntu 16.04 next to Windows 10. Windows is installed on legacy bios and then upgraded to Windows 10. When I try to install Ubuntu from USB stick, it shows a message titled "Force UEFI installation?". It says that the machine's firmware started the installer in UEFI mode but there is an OS installed using BIOS compatibility mode. If I force installation I won't be able to boot Windows.

How can I start the installer in legacy mode?

BIOS of the machine supports legacy and UEFI modes. Legacy support is enabled. But USB disk is always recognized as EFI. USB disk's name is shown as "EFI USB Disk" in BIOS. I cannot change that. I burned the USB with both startup disk creator on ubuntu 14.04 and pendrive software on Windows. Same result.

Thanks.

zarax
  • 191
  • 1
  • 10
  • 1
    Just say no to UEFI when asked -or- boot it properly from the start -or- disable UEFI altogether in UEFI settings. Honestly, you're creating problems where there's none. –  Jan 04 '17 at 17:01
  • 1) I never got a question about UEFI. When do you get it? 2) How to boot it properly? I tried changing boot mode, priority bios mode etc. Nothing works. 3) There are only two settings: UEFI and Legacy Support. Both of them works with UEFI. It cannot be disabled. 4) There is a problem which I did not create. – zarax Jan 04 '17 at 17:44
  • 1
    1) *it shows a message titled "Force UEFI installation?"* <- **This** message, just answer "no" and the installation will proceed in Legacy mode; 2) When both UEFI and Legacy are allowed, a USB flash will be listed twice, one preceded by "EFI" (or "UEFI") and other withou it; 3) The usual is UEFI only, UEFI+Legacy and Legacy only; please EDIT your question and post the brand/model of such unusual machine; 4) This is NOT a forum. Whenever a troubleshooting with such back & forth (like we're having now) is needed then other resources like the Ubuntu Forums are more suitable than our Q&A format. –  Jan 04 '17 at 17:50
  • 1) When you click no, it will stop there. Not continue. 2) USB is only listed once: EFI. 3) Legacy only is not available. It just a lenovo laptop.4) Then what is the purpose of askubuntu? To scold other people? – zarax Jan 04 '17 at 18:03
  • 1
    The puprose of a Q&A is to be a "question & answer" format, that's all. Again, it's not for extended troubleshooting. Again, please edit your question with the relevant information regarding the **exact** make/model. Thank you. –  Jan 04 '17 at 18:06
  • 1
    Related: http://askubuntu.com/questions/221835/installing-ubuntu-alongside-a-pre-installed-windows-with-uefi and – Elder Geek Jan 04 '17 at 18:33

1 Answers1

5

You've got a BIOS/CSM/legacy-mode installation of Windows, but you booted the Ubuntu installer in EFI/UEFI mode. The two modes can be made to coexist, but doing so is tricky. It's generally better to boot the Ubuntu installation medium in BIOS mode. Broadly speaking, this can be done in either of two ways:

  • Learn to control your boot mode -- Most EFIs provide some means to control whether they boot in BIOS mode or in EFI (native) mode. Unfortunately, details vary greatly from one system to another. In many cases, though, when you access the boot manager that enables you to boot from a CD-R or USB flash drive, you'll see two options for the external medium, one of which includes the string "UEFI" and the other of which does not. Select the "UEFI" option to boot in EFI mode and the other one to boot in BIOS mode.
  • Prepare a BIOS-only boot medium -- If you prepare the USB flash drive in a way that omits the EFI boot loader, it can't boot in EFI mode. Some tools for preparing bootable USB drives, like Rufus, give you good control over the boot loaders included on the disk. Others don't, although you can usually delete the EFI boot loaders from prepared USB drives. (The key file is EFI/BOOT/bootx64.efi for an x86-64 system.) If you're booting from an optical disc, adjusting the boot loaders on it is much more complex.

Note that these two approaches are intertwined; you can't boot to BIOS mode if the boot medium lacks a BIOS-mode boot loader, no matter how hard you try. Thus, if you have trouble controlling the boot mode, you may need to re-examine how you prepared the Ubuntu installation disk, since that method might have omitted the BIOS boot loader. Also, some computers offer such poor boot managers that you may not be able to control their boot modes except by adjusting the boot medium.

If you need more information on this subject, see this page of mine. Note that it's written mainly for people who have EFI-mode Windows installations and who might be accidentally booting the Linux installer in BIOS mode, which is the opposite of your problem; but the basic information is still relevant.

Another way to solve your problem is to convert your BIOS-mode Windows installation into an EFI-mode installation, as described on this blog post. You could then install Ubuntu in EFI mode. In the long run, this may be a cleaner solution than booting both OSes in BIOS mode, for the reasons described on my CSM page; however, this approach will be much harder and riskier in the short term. Thus, it's probably better to stick with a BIOS-mode Ubuntu installation for now unless you have some other compelling reason to make the switch.

Eliah Kagan
  • 116,445
  • 54
  • 318
  • 493
Rod Smith
  • 43,599
  • 7
  • 62
  • 102