No detected operating system

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reuhop
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No detected operating system

Post by reuhop » Sun Jun 24, 2018 11:29 pm

This is my first time trying to install Linux Mint. I have an Acer Aspire E 15. I got into BIOS and went into legacy mode for boot because it wouldn't allow me to use USB boot otherwise. Linux Mint started up and I went to install it. When I get to installation type, it says there is no operating system detected even though I have Windows. I'm trying to do a dual boot and I don't want to erase everything on my computer. But it's only giving me the option to erase disk and some other ones I don't understand. I've tried getting back to BIOS but it now only automatically boots up with Linux Mint. If I don't have my USB in, it shows me errors and I have to restart with the USB so I can at least get it to show something. If I can't download Linux without erasing everything, I at least want to get back to Windows so I can use all my programs.

gm10
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Re: No detected operating system

Post by gm10 » Mon Jun 25, 2018 4:23 am

Your Windows was installed in EFI/secure boot mode, you locked yourself out by switching to legacy mode. You should switch the BIOS back to EFI mode to access your Windows installation. Or if you want to stay in legacy mode, you'll probably need to re-install Windows - it may be possible that booting from a Windows repair/recovery disc/USB allows you to fix your existing Windows for MBR (legacy) boot automatically but I don't know, never tried.
Tune up your LM 19.x: ppa:gm10/linuxmint-tools

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michael louwe
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Re: No detected operating system

Post by michael louwe » Mon Jun 25, 2018 4:33 am

@ reuhop, .......
reuhop wrote:.
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Please refer to ... http://www.rodsbooks.com/efi-bootloader ... ting-media
(Creating EFI-Bootable USB Drives)
https://etcher.io/
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.

For some guidance on dual-booting LM alongside Win 10/8.1 in UEFI and GPT-disk mode, please refer to .......
viewtopic.php?f=42&t=163126 (Tutorial for dual-booting UEFI computers)
http://linuxmint-installation-guide.rea ... en/latest/
https://ubuntuforums.org/showthread.php?t=2147295
https://sites.google.com/site/easylinux ... ct/windows
https://sites.google.com/site/easylinux ... nt-install
https://www.tecmint.com/install-linux-m ... uefi-mode/ (note step 17 - if Win 8.x/10 could not boot, <sudo update-grub>)
viewtopic.php?f=42&t=122276 (manual partitioning Tutorial for Legacy BIOS mode and MBR/ms-dos disks)[use as a guide]

Ensure that Secure Boot, Fast Boot and CSM(or Legacy BIOS) are disabled in BIOS setup, Fast Startup is disabled in Win 10/8.1(>Control Panel >Power options) and the Live LM media(DVD or USB-stick) is booted in UEFI mode in BIOS setup.

To dual-boot, you only need to pre-shrink the Windows partition if you intend to use the manual "Something else" install method, ie no need to do so if you intend to use the automatic "install LM alongside Windows Boot Manager" method, which will be followed by the LM Installer auto-partitioning the disk and auto-installing the Linux Grub bootloader onto the Windows ESP. Only a root / and swap partition will be auto-created with a total default size of about 20GB. The user will be given the option to increase this default size by moving a slider on the colored Partition table, subject to the maximum available free space in the Windows partition.

For the "Something else" install method, manually partition the pre-shrunk free space accordingly, eg 50GB for /, 1.5X RAM size for Swap(at the end of this space) and 200GB for Home; and ensure that the "Device for boot loader installation" is the Windows EFI System Partition(= ESP = fat32/about 104MB/mount point is /boot/efi) which is usually dev/sda1.
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P S - Certain OEM Win 8.x/10 computers, eg Acer, Asus and HP, have an obstructive or pro-M$ UEFI-BIOS setting for "select an UEFI file as trusted for executing",(= Linux cannot boot). For the fix, please refer to ...
https://community.acer.com/en/discussio ... 15-51-78c6
https://itsfoss.com/no-bootable-device-found-ubuntu/
viewtopic.php?t=236560

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