Questions tagged [grub2]

GRUB 2 is the next generation of the GRand Unified Bootloader (GRUB). Ubuntu has used GRUB 2 as the boot loader since 9.10 (Karmic Koala). Commonly referred to as simply "GRUB".

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733
votes
38answers
1.1m views

How do I remove old kernel versions to clean up the boot menu?

Every time I install a new Linux kernel, it gets left in the grub_config, making the boot menu longer each time. I know I can manually search through the installed packages and remove them. Does ...
390
votes
14answers
882k views

How can I repair grub? (How to get Ubuntu back after installing Windows?)

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu. How can I get Ubuntu back?
385
votes
6answers
1.6m views

How do I change the GRUB boot order?

I have both Windows 7 and Ubuntu installed on a shared machine. Because a lot of the non-developers use Windows, I'd like to change the boot order to make it easier for them. Currently the boot order ...
356
votes
9answers
1.0m views

How to get to the GRUB menu at boot-time?

My system is not dual-boot, I run a standard Ubuntu desktop system "on the metal" (I think running it in a VM is the same). Pressing c while booting does not cause the GRUB menu to appear (which I ...
264
votes
16answers
786k views

How do I set Windows to boot as the default in the boot loader?

How do I set the bootloader so that in my dualboot with Windows 7/Ubuntu 11.04, Windows start up as standard instead of Ubuntu?
227
votes
10answers
762k views

How do I set the grub timeout and the grub default boot entry?

In Ubuntu 12.04 (or above), how do I set the GRUB time and the default OS (that I see at boot time) as I'm dual-booting Windows (7/8) and Ubuntu (12.04 or above)?
198
votes
3answers
513k views

How do I add a kernel boot parameter?

I need to add the boot parameter foo=bar to my kernel. How can I do this once for testing, and permanently if testing was a success?
176
votes
12answers
989k views

Uninstall GRUB and use Windows bootloader

I have Windows 8 pre-installed, and then I installed GRUB with Ubuntu. Ubuntu is not my thing, so now I want to remove it along with GRUB. From what I have learned, with UEFI, GRUB does not overwrite ...
154
votes
3answers
156k views

How do I re-run boot loader?

Running sudo apt-get -f install said that The link /vmlinuz.old is a damaged link and: you may need to re-run your boot loader[grub] Here's the full output: user@chrubuntu:~$ sudo apt-get -f ...
132
votes
5answers
176k views

How to get grub2 to remember last choice?

Grub2 - Community Ubuntu Documentation says the following: Saving an OS can be achieved by running sudo grub-set-default if DEFAULT=saved is set in /etc/default/grub. It may also be saved if ...
119
votes
3answers
544k views

How do I set 'nomodeset' after I've already installed Ubuntu?

I know that editing the boot options line and adding 'nomodeset' solves the problem of my laptop during LiveCD mode, what I don't know is how to set it at boot up through Grub2 after I've installed ...
117
votes
5answers
263k views

Set “older” kernel as default grub entry

I installed a mainline kernel for testing purposes. I would like to set grub to boot from the older kernel by default. I know I can set the GRUB_DEFAULT=0 setting for the first page of grub but how ...
112
votes
2answers
84k views

What do I select for “GRUB install devices” after an update?

After running Update Manager, a debconf window (titled "Configuring grub-pc"), popped up, requiring me to select the appropriateGRUB install devices for my system. I've made no changes to grub or ...
103
votes
14answers
314k views

Windows 10 upgrade kills grub and boot-repair doesn't help

I've just upgraded to Windows 10 from Windows 8.1 on my partitioned laptop that has Ubuntu 14.04 installed. Grub no longer appeared on boot so I ran boot-repair from an Ubuntu liveUSB. This didn't ...
103
votes
6answers
188k views

How can I show or hide boot messages when Ubuntu starts?

Is there a way to easily turn on/off showing the boot messages (loading the services) when Ubuntu starts? Is it something in Grub2? I am running 10.04.
97
votes
4answers
429k views

How do I boot into single-user mode from GRUB?

After changing a few lines in xorg.conf, I can no longer boot Ubuntu (I assume it breaks when trying to load up X), so I need a way to boot into a single-user mode. However, there seems to be zero ...
90
votes
2answers
97k views

Diskfilter writes are not supported > What triggers this error?

This message occurs when leaving the Grub menu and before the Ubuntu splash screen. How do I fix the problem to clear the message? And what doe is it mean? error: Diskfilter writes are not ...
87
votes
12answers
395k views

GRUB does not detect Windows

I have finally installed Ubuntu on my second drive. When I start my computer GRUB only offers me to boot Ubuntu, not Windows 7. What needs to be done so that I can choose between Ubuntu and Windows in ...
85
votes
12answers
251k views

16.04 new installation gives grub-efi-amd64-signed failed installation /target/ ubuntu 16.04 at the end

I am installing Ubuntu 16.04 in an Intel NUC computer with UEFI enabled. I am using an SSD from another computer. During the installation I chose Erase the disk and make a new full install At the end ...
83
votes
2answers
99k views

What is the difference between GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub

I'm troubleshooting a fn-key brightness control problem on my laptop, so I'm wading through a lot of config options in /etc/default/grub, as you can imagine. However, it's raised a question for me: ...
82
votes
1answer
47k views

Can I boot a Live USB fully to RAM, allowing me to remove the disk?

I have a live USB made with the standard Ubuntu disk image creator for 16.04 LTS. In the current state, I can boot to this disk, but it still requires the original USB to run properly at all times. ...
80
votes
4answers
250k views

How can I change/convert a Ubuntu MBR drive to a GPT, and make Ubuntu boot from EFI?

I recently have upgraded my PC, my new Motherboard (ASUS M5A99X EVO) uses UEFi instead of the regular MBR option. I have a Ubuntu 11.10 installation that I did when I had my previous hardware (MSI MS ...
80
votes
5answers
255k views

Windows 10 upgrade led to grub rescue

I was dual-booting Windows 7 and Linux Ubuntu on my desktop, and today is the day they gave out free Windows 10 upgrades. How exciting! I got the update, and it was installing, and I left to go take ...
77
votes
1answer
199k views

How do I boot into a root shell?

When booting to the graphical desktop fails we sometimes are recommended to boot into a "root shell" or to boot in "recovery mode". How do I do that?
76
votes
4answers
883k views

GRUB rescue problem after deleting Ubuntu partition! [duplicate]

After I deleted my Ubuntu partition, I rebooted my computer and I only get a prompt: grub rescue > The command ls lists (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (hd1) (hd1,...
76
votes
6answers
192k views

How do I run update-grub from a LiveCD?

Okay, so I did something stupid. I was trying to clean up my Grub entries, and accidentally removed all of my Linux kernels from Grub (they're still on the hard drive). So now, obviously, Grub doesn'...
74
votes
7answers
13k views

How to secure my laptop so that hacking by physical access is not possible?

I messed up my system earlier, I was greeted with a black screen, when booting in to Ubuntu. When I started up my laptop, I selected the recovery option from the grub menu, and chose fallback at root ...
71
votes
9answers
332k views

How can I boot with an older kernel version?

The latest kernel is causing problems with my sound, which worked fine with an older version. As I have only Ubuntu installed, Grub is not getting displayed while booting. How can I manually choose my ...
70
votes
6answers
898k views

How to fix "error: unknown filesystem. grub rescue> [duplicate]

I get this error: Error: unknown filesystem. grub rescue> I'm not exactly sure what I did. I believe I installed Ubuntu over Windows on my Acer netbook. I then tried to install Linux Mint, but it ...
69
votes
12answers
250k views

How can I reinstall GRUB to the EFI partition?

I want to reinstall GRUB 2 and I found these instructions: How to Repair, Restore, or Reinstall Grub 2 with a Ubuntu Live CD or USB. In my case, the boot loader is installed in the EFI partition. If I ...
69
votes
6answers
430k views

Recovering GRUB after installing Windows 7? [duplicate]

Possible Duplicate: How can I repair GRUB? (How to get Ubuntu back after installing Windows?) I installed Windows 7 after it crashed, and now I am unable to boot Ubuntu. Ubuntu partitions ...
68
votes
5answers
40k views

How do I apt-get -y dist-upgrade without a grub config prompt?

Per Make apt-get (or aptitude) run with -y but not prompt for replacement of configuration files? I did the following: ec2run ami-3c994355 --region us-east-1 -n 1 -t m1.large -z us-east-1d On the ...
68
votes
5answers
260k views

How to safely change grub2 screen resolution?

grub2 isn't really fit in the best screen resolution that my laptop can support (1280 x 800). How can I do this without using a third party application ?
65
votes
6answers
388k views

Grub rescue - error: unknown filesystem

I have a multiboot system set up. The system has three drives. Multiboot is configured with Windows XP, Windows 7, and Ubuntu - all on the first drive. I had a lot of unpartitioned space left on the ...
61
votes
18answers
236k views

How do I hide the GRUB menu showing up at the beginning of boot?

I stopped dual booting and I don't want to have to choose the OS any more. I want to boot into Ubuntu 12.04 directly without seeing the GRUB menu. How can I achieve that?
61
votes
1answer
62k views

What is the difference between update-grub and update-grub2?

I'm making some changes on my grub file under /etc/default/grub. In some tutorials I have seen sudo update-grub and others sudo update-grub2. What is the difference?
57
votes
4answers
94k views

How to return from grub prompt to the grub menu?

If you press escape in grub menu you end up at the grub command prompt. My question is, how can I go back to the menu, without rebooting?
57
votes
3answers
55k views

How do I find the boot parameters used by the running kernel?

Is there a way to find out with what parameters did the kernel boot? For example if I specify noexec=off at the grub command line? Can I see this sort of info after the system has finished booting?
57
votes
1answer
108k views

Dual boot Surface Pro with Ubuntu?

How could I setup a dual boot for Ubuntu and Windows 8 on my Microsoft Surface Pro with 128 GB. Note: My dual boot solution is below.
55
votes
6answers
468k views

Failed to get canonical path of /cow

I am trying to install Ubuntu 12.10 for quite some time, and passing hurdles one by one. Now I am in a situation as follows. I have got a PC and 10 GB HDD which will be totally dedicated to Ubuntu so ...
53
votes
7answers
282k views

How can I edit my Grub bootloader entries (Hide, Rename, Remove)?

So basically I have a pretty flooded Grub bootloader, with older linux versions, 3 operating systems and memtests. What I want is to leave the operating systems only. I need to know how to do it ...
51
votes
7answers
112k views

How to know the version of GRUB

How do I find the version of GRUB that is running in a particular version of Ubuntu? I want a terminal command that tells me.
51
votes
5answers
456k views

error: file '/grub/i386-pc/normal.mod' not found

error: file '/grub/i386-pc/normal.mod' not found. grub rescue> What can I do? I just sit and stare at it. I found my old netbook (Dell Inspiron 1010) which I have not used for about four years. ...
51
votes
3answers
43k views

Ubuntu 16.04 slow boot (apt-daily.service)

My boot is horribly slow, and I don't know why. $ systemd-analyze Startup finished in 10.975s (kernel) + 49.732s (userspace) = 1min 708ms $ systemd-analyze blame 34.971s apt-daily.service ...
51
votes
11answers
79k views

How to fix a grub boot error : "symbol 'grub_calloc' not found

Just ran the latest batch of updates on 20.04 (Xubuntu), and now I'm getting a GRUB error: symbol 'grub_calloc' not found I'm dropped into the 'grub rescue' shell, but have no idea what to do there ...
49
votes
9answers
322k views

Add Windows 10 to GRUB OS list

I recently got a computer from school. It came with Windows 8.1 installed. I then installed another copy of Windows 8.1 (so it would use the built-in Windows Pro license) and upgraded it to Windows 10....
45
votes
6answers
84k views

How can I add the Memtest86+ options back to the Grub menu?

If using UEFI Please see this question, "Can I boot memtest86+ if I'm using UEFI?" After having installed the 64bit version of Ubuntu 12.04 on my Lenovo B570 I ran into the same problems I had when ...
44
votes
19answers
206k views

Unable to boot into Windows after installing Ubuntu, how to fix?

I installed Windows on my computer, followed by an installation of Ubuntu. However, now I'm unable to boot into my Windows install. What can I do to fix this?
44
votes
3answers
34k views

Grub update warning in Ubuntu 14.04

I tried to update Grub so I run: sudo update-grub Generating grub configuration file ... Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported. ...
43
votes
6answers
69k views

How to change the purple background color in grub?

How to do this manually, not installing any tools?

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