Installed 17.1 on dual-boot PC, but no GRUB, and no login/desktop
 

I ran a 17.1 live DVD, which seemed to work okay, so I installed from there. My drives are:

sda - existing Windows 8.1 partition
sdb - existing NTFS partition - added 1 partition root, and 1 partition swap
sdc - existing NTFS partition

Mint did NOT see that I had Win 8.1 installed, but as I was doing the partitioning manually this probably was not an issue.

I installed everything to the new partition on sdb, rebooted, then changed the boot order to check sdb before sda.

What happens next is:

1. I don't see the familiar GRUB menu, but it does go straight through to the black loading screen with the green and white Mint logo. So I don't get to choose Windows (or compatibility mode, or any other options that might or should be there)
2. Then the screen goes black and my monitor goes into standby. My main graphics card is an AMD one, but there is also onboard graphics too. In the past I've found Linux distros get very confused over which card to use so I tried connecting the monitor to the onboard gfx ports, but there didn't seem to be any signal there either.

The system doesn't appear to have hung at this stage - caps lock still toggles on and off, and the first time this happened there was a lot of periodic disk activity, as if it was downloading updates in the background, or finishing the installation process.

So, how can I (a) actually get Mint to show something on-screen, and (b) get GRUB working and allowing me to choose between Mint and Windows?

The Grub menu won't show if it is only aware of one operating system (Mint) so apparently, the windows wasn't detected.
You have windows 8.1 installed on sda, was that pre-installed? If so, it is likely in UEFI/GPT. Did you install Mint UEFI/GPT? If not, you would see the problems you are experiencing. If you did, then it is some other problem. If I understand correctly, you cannot boot the installed Mint, correct? You might try booting the Mint installation medium, opening a browser and googling bootinfoscript. When you get to the site, download and run it from Mint and post the output here, a results.txt file. There are instructions in a link in the Description box on the bootinfoscript page. That should give enough information for someone to make suggestions.

I don't fully understand the UEFI system (as I've not upgraded many systems in the last 5 or 6 years) but my understanding is that yes, UEFI is enabled, but it is also in a state that allows legacy booting as well, and I suspect that it may be booting Windows via the legacy system.

I didn't download any special version of Mint: I just went to http://www.linuxmint.com/download.php which makes no mention of a "Mint UEFI/GPT" so I don't really know what that means. I got the regular 64-bit Cinnamon version. The release notes say to ensure that "secureBoot is off", but I have no secureBoot option in my BIOS/UEFI interface.

Here's what bootinfoscript has to say:
Boot Info Script 0.61 [1 April 2012]


============================= Boot Info Summary: ===============================

=> Windows is installed in the MBR of /dev/sda.
=> Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector
1205141792 of the same hard drive for core.img, but core.img can not be
found at this location.
=> Windows is installed in the MBR of /dev/sdc.

sda1: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files: /bootmgr /Boot/BCD

sda2: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files: /Windows/System32/winload.exe

sdb1: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: According to the info in the boot sector, sdb1 has
1053562879 sectors, but according to the info from
fdisk, it has 2127304703 sectors.
Operating System:
Boot files:

sdb2: __________________________________________________________________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Linux Mint 17.1 Rebecca
Boot files: /boot/grub/grub.cfg /etc/fstab

sdb3: __________________________________________________________________________

File system: swap
Boot sector type: -
Boot sector info:

sdc1: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: According to the info in the boot sector, sdc1 has
1565562879 sectors, but according to the info from
fdisk, it has 2639304703 sectors.
Operating System:
Boot files:

(I'll attach the file for the rest, if it's relevant.)

Funny that the script can detect Windows just fine when the installer cannot.

Something went wrong with the installation of the Grub bootloader as you can see from the message above. It won't boot without the core.img file. Reinstall Grub2 from the Mint installation medium using the instructions at the link below;

https://help.ubuntu.com/community/Gr..._Broken_System

There is no indication of UEFI but the larger drive with Mint on it shows GPT boot. I don't use GPT and don't have much knowledge of it so I won't make any suggestions.

You have installed Mint in legacy (msdos) mode to a drive with GPT partitioning. That is not a good thing.
GPT does not have the old style MBR where Grub would be installed. Instead, it has a "fake MBR" to accomodate legacy installations.
Here is a good tutorial on how to fix it - http://www.rodsbooks.com/gdisk/wipegpt.html

TxLonghorn, if the installer has done the wrong thing that is its fault. I installed everything to the recommended locations, and followed defaults apart from where it suggested wiping the disk because it failed to spot my Windows 8.1 installation on sda. It's obviously possible to see what state the boot system is in (as the boot info script shows everything, it seems) so it shouldn't really have gone ahead if it is going to create a broken install. Thanks for the "wipegpt" tutorial but that looks too complex and potentially damaging given that I have an NTFS partition on that disk that I want to preserve. Is there a simpler alternative? The 2nd person in this thread appears to have achieved exactly what I was trying without any special treatment necessary, for example.

yancek, I tried the Boot-Repair application (why isn't that in the package manager, incidentally?) and it initially refused to do anything, because of the GPT booting. Specifically, it said: "GPT Detected. Please create a BIOS-Boot partition" (>1MB, unformatted filesystem, bios_grub flag). This can be performed by tools such as GParted. Then try again." So I've done that, but am waiting before trying the boot repair again, in case someone else has some feedback to give.

Hi;i don't know much about this partitions stuff, but what i know is that i never bothered to do partitions manually, i always let the the system do it for me,i first install Win and then install Linux and when in linux after all updates i type ''sudo apt-get update grub'' and reboot,when i reboot i have a menu with Linux and Win,if i don't choose OPS it boots right up to Linux,i like it this way, i don't mess with partitions and everything runs smooth,but then again it's my choice.

I agree with that - up to a certain point. The install program could be better. But, it is created to accommodate two very different types of installations, UEFI and legacy. One is meant for GPT and the other for msdos partitioning. If you mix the wrong partitioning with the wrong installation procedure - that is operator error.

At which point in the installer process do you think it provides that sort of choice to the user? There is absolutely no mention of UEFI or GPT during the install process at all, nor before it in the docs. The only choice I was given was whether to "erase disk" (not an option - there is a partition I want to keep) or "something else" (create partitions manually via an interface that has not improved in usability since I first installed Mandrake in the 90s).

True. As I said, the installer could be better. But, the option of booting the installation DVD or USB in either UEFI mode or msdos (legacy) mode is provided in your computer's BIOS. It is not an option presented by the live DVD (or USB). I agree completely that it should be.
I will try to make it simpler for you...
LINK TO DISCUSSION ABOVE

I don't need the installer to let me make that change; I need it to explain why UEFI should be a problem before it makes a botched attempt at installation that can never work. I have my BIOS set to work in "UEFI and Legacy" mode, and Mint supposedly has UEFI support anyway. It seems clear from various posts online that it is possible to boot Mint from UEFI/GPT. It just seems that the installer has no idea how to do that and everybody's guide on how to do it seems different (one says you need a 1MB partition flagged as bios_grub, another says you need a 512MB partition formatted as 'efi', one says you need both but that it's impossible to dual boot).

Incidentally, I load up the live/installer CD from UEFI mode, as that is how it detects the DVD drive as a boot device. But that makes no difference to Mint when it actually starts installing, apparently.

Thanks for the simplification on how to use wipe the GPT data; however, on the fixparts documentation page it says "If you're not sure whether to delete the GPT data, don't do it; type N, exit from the program by typing q at the main prompt, and investigate further." I'm not sure that I want to wipe it, since it's not clear that I should.

I don't use UEFI or GPT. You can use GPT with UEFI or without it. You can use it without UEFI if you create a small BIOS boot partition.
If you are using UEFI and GPT, you do NOT create a BIOS boot partition but rather a FAT32 partition which is usually near the beginning of the drive, most often the first partition, and it contains the efi boot files for your operating systems. In your case, it would have both the windows efi files as well as the Mint efi files which will actually be named ubuntu. I don't see any partition with those files so it looks like GPT without UEFI. Also, your bootinfoscript is incomplete for some reason.

That would be pretty unusual as it is usually an either/or, UEFI or Legacy but different manufacturers have different options in the BIOS which is another reason it is difficult to give a single answer.

Okay, I did a lot more reading and a bit more tinkering and the good news is that I have Mint installed now. For the benefit of anybody finding this on Google or whatever, the trick was to create an EFI partition (200MB, FAT32, flagged 'boot', then put the boot loader there during installation and designate it as an EFI partition) and since the BIOS had that as the first choice, it boots straight into Mint now.

Unfortunately there is still no GRUB2 menu as it can't find Windows 8.1. I tried the os-prober and update-grub routes but neither found it. So I can only choose between operating systems by reordering the BIOS boot order - not optimal.

My disks are a bit unusual: Windows 8.1 is on a smaller, MBR disk. Linux Mint is on a 3TB GPT disk. (Both according to Windows disk management, at least.) Maybe if Windows was also on a GPT disk there would be no problem, but that's not something I can change easily now.

If anybody has any suggestion on how I can force GRUB2 to find Windows on the other disk, and show me a menu to let me choose between them, I'd be grateful.

try putting the /boot/grub/grub.cfg file on the the efi partition with boot loader

edit the menu may also be hidden hit the esc key at first boot to see if grub menu will show

Unless you have modified your windows install since your earlier post with the bootinfo summary, windows was installed using MBR BIOS and you installed Mint using EFI so I think with that setup, your only option is to select the drive in BIOS. I'm not sure what difference it makes that they are on separate drives, if any. I did read a post on another forum of someone who 'said' they had one OS in MBR BIOS and the other EFI but didn't post any info on how he did it so I don't know if it can be done. Hang on, someone else might come along with more info.

That won't work, the grub.cfg file should be on the partition. The files on the FAT32 partition will have 'efi' and 'ubuntu' in their names.