I am a newbie (used Ubuntu about 5 years ago, but forgot the little I learned). I installed Ubuntu 16.04 LTS about a week ago, and it's great. This week, I decided to try Mint 18 Sarah to compare. I also love it, since it's similar to Windows, which I'm so familiar with.
My problem is, Mint is the default at startup. I did some research and tried to edit the start order in GRUB. When I do this in Ubuntu, I don't see an entry for Mint. When I try in Mint, I don't see an entry for Ubuntu.
is there a Master GRUB file somewhere that I can edit within either distro?

IN order to get that one Linux Disto you want to be on the top of the list to boot from. You have to get it to have dominance over all of the others. (grub2).

Therefore, after installing any other Linux distos letting that install - install grub2 for reasons to avoid having problems getting it to boot. just GO BACK into that one special Linux Distro you love to have on the top of the list, and do this:
that will give it prominence over the others. done. have a nice day

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If Mint is the default at startup, then it is likely controlling the MBR so you should run: sudo update-grub from Mint and watch the output. You should see an entry for Ubuntu. I'm surprised an entry was not created for Ubuntu when you installed Mint as other Linux systems are usually detected.

The file you need to edit is /etc/default/grub, change the line below to show the correct number. Count is from zero so if the entry you want is 3, you would need the number zero on that line. You need to run: sudo update-grub after making this change.

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Hi ChunkyDrew1965.

Grub, especially grub2, is a bit difficult to work with manually - especially because it generates a bunch of the menu entries on the fly when it is updated.

It gets a bit worse if you have an older distro which uses grub 1. That uses a different menu and files. Changes made there don't get seen by another distro using grub2 and vica verse. I had this problem while I was running 12.04 and working on configuring 16.04 in another partition.

There's a really great tool which makes it way easier to deal with. It's called grub-customizer and is available from a PPA for Ubuntu.

https://launchpad.net/grub-customizer

I've been using it for years. It lets you see what you're doing in a gui. You can move entries up and down, create sub-menus, change fonts and colors, and even set a background (wallpaper) image.

It will find whatever is on your disk (including Windows, if it's there) and add it to your menu. Then, you can choose which entry is the default one. It's usually the one at the top of the menu.

I have my menu setup to have the current default and recovery version at the top. All the previous versions are in a sub-menu so I don't have to look at them. I have another sub-menu for the previous release of Ubuntu or for the next one that I may be working on in other partitions.

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You may like to re-phrase that yancek.No - as indicated above, each install will have its own file(s).
Worse, updates to either may update the boot menu at random times in future. Usually pays to designate one as the "master", and re-install manually in need.

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Will that make Ubuntu boot first from now on?

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Sort of. The problem is that you have one set of menus for each OS. Everything will be fine *until* the one you are running at the moment gets a kernel update. When that happens, it will update its copy of the grub menu.

Then, one of two things (that I have run into) will happen.

1) If the menu that gets updated is the one that gets activated when you boot, then everything will be fine.

2) If it's not the one that runs, you won't see the changes the next time you boot (including the new kernel you just installed) and if you delete a few older kernels, then the boot menu you get won't have any live choices for this OS.

You can triage this problem by rewriting the master boot record (MBR) on your boot drive so it will use the menu you just updated.

I don't remember how to do this manually. Grub-customizer has a button for that (and it gets it right if you have a UEFI boot process too.)

The reason grub-customizer (and doing it manually the right way - see other posts) works is that it rescans the actual disk drive and makes sure that whatever it finds is what ends up in the menu, no matter where it came from. Then, all you have to do is make sure that the menu you just rebuilt is the one the boot process uses.

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If you are a newbie there is a tool that you will find very useful called Grub Customizer. Use it with caution but if you follow all the instructions and read the included Help facility you will have no problems. Go to https://launchpad.net/~danielrichter...rub-customizer and read the installation instructions. If you strike any issues you can contact the developer, Daniel Richter, who you will find to be very helpful. Cheers, gblacks.

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Thanks josephj

I usually edit the grub2 itself and save it. This cool tool is very handy. I am using it to manage my Ubuntu 16.04 LTS, Windoz 10 and Mint menagerie.

Thousands of thanks!

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Great. It makes my day when I can actually help someone instead of always being the one asking for help.

If you want to, you can mark my post(s) as helpful. It's easy to forget to do that on LQ.

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