I currently have Windows 7 and Linux Mint installed.

When my pc starts up, it shows me the Grub menu, it shows an entry for Mint linux and the windows boot menu.

I am wondering, if i was to install Elementary OS, would it be automatically added to grub or do i have to put some command in the terminal?

I also want to ask, when i boot from my Elementary OS cd, and install it, just before it finishes, it shows some kind of error saying some error about cannot install to grub or something, ive tried installing to a separate partition and alongside "Them", but had no luck.

I'm really new to Linux, and want to keep my Mint Linux and Windows 7 because i have files on them

  • Yes, the Elementary OS boot entry should be displayed along the others in the GRUB boot menu. Could you paste the error you get ? It would be helpful for better answers. By the way, generally speaking, it would be better to install the GRUB bootloader in the disk where the OSes you got are stored. – Pavel Rizzo Feb 2 '16 at 21:47
  • PART 1: Obviously do a back up before trying, so you can play as much as you want with your computer with no risk of loosing data. Installing os as famous as the ones we are talking posses no risk of damaging the computer, but it may result in inability to boot, it has happened me that sometimes they are installed but don't get recognized by the boot manager (such as grub).... – Santropedro Feb 2 '16 at 21:51
  • PART 2: Possible lines of attack are Boot repair and reinstalling grub (there are many ways, such as installing a Linux OS and installing grub from there or using some live cd ). I can't answer specifically to Elementary OS and Mint, I have not used them. I have Windows 7, Debian and Ubuntu, installed – Santropedro Feb 2 '16 at 21:57
  • PART 3:on that order, and they appear all in boot process, Everytime you install a new Linux the boot manager gets replaced by the new Os grub version (or other boot manager) sometimes it's the same (grub 2 in my 2 linux) but you can realize because the grub2's wallpaper changes to the last OS you installed. If you loss a OS but you have at least a linux distro working, you can do that I said earlier of reinstalling grub2, I have done it in Ubuntu and has recognized a lot of OS that were not recognized for some – Santropedro Feb 2 '16 at 21:57
  • PART 4: reason. The order of installing matters a lot. You will install elementary now so research the capabilities of elementary OS uninstalller, after installing it at least elementary will work and from there you can probably reinstall grub. Use the OS-prober package to troubleshot and detect OS (well, that package it's on debian and Ubuntu, so because Elemenraty it's based on Ubuntu, it should be. As a last thing, I'm not any kind of expert, but the info I said here it's pretty true. Be cautios and wait for a response of some triple-booter elementary OS user. – Santropedro Feb 2 '16 at 21:58

GRUB relies on configuration files that are typically written in the host OS -- Elementary OS or Mint, in your case. What's likely to happen is that, when you install Elementary OS, its version of GRUB will take over the boot process. It will probably make Elementary OS the default but detect the Mint installation and make it possible to boot it as a secondary OS. If you want to change your GRUB configuration, you'll need to either do so from Elementary OS or re-install GRUB from Mint.

Many people who multi-boot different Linux distributions prefer to install a boot manager that's at least somewhat independent of each distribution. On a BIOS-based system, this could be a version of GRUB that's not tied to either distribution or something else, like LILO or SYSLINUX. On an EFI-based computer, GRUB, ELILO, and SYSLINUX are all possibilities, as are rEFInd, rEFIt, and gummiboot/systemd-boot. Most of these require either manual configuration or chainloading to the distribution-centric versions of GRUB. rEFInd, though, detects kernels at boot time, so it requires little or no maintenance when each distribution updates its kernels. See my EFI Boot Loaders for Linux page for more on the EFI options.

As a broader comment, Elementary OS, Mint, and Ubuntu are all pretty similar. They've got different default GUIs, but it's possible to install multiple desktop environments in one distribution. You may be better off doing this than trying to deal with the multi-boot problems. See, among other places, this AskUbuntu question and answer for some pointers on getting started with this approach. I'm pretty sure that Mint's common desktop environments are available in Ubuntu (and therefore in its derivatives, including Elementary OS). I don't know if you can easily get an Elementary OS "look and feel" out of a stock Ubuntu or Mint, though.