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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693
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 ...
337
votes
12answers
681k 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?
330
votes
5answers
1.4m 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 ...
259
votes
7answers
691k views

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

This issue came up recently for me (and I've been prompted to lodge it as a specific question about it): My system is not dual-boot, I run a standard Ubuntu desktop system "on the metal" (I think ...
232
votes
16answers
672k 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?
189
votes
8answers
606k 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)?
150
votes
3answers
360k 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?
150
votes
3answers
153k 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 ...
98
votes
3answers
397k 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 ...
97
votes
4answers
122k 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 ...
90
votes
4answers
193k 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 ...
87
votes
2answers
88k 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
2answers
60k 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 ...
84
votes
6answers
153k 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.
83
votes
13answers
271k 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 ...
78
votes
4answers
356k 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 ...
74
votes
11answers
189k 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 ...
73
votes
7answers
11k 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 ...
73
votes
1answer
27k 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. ...
72
votes
5answers
238k 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 ...
72
votes
1answer
161k 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?
70
votes
4answers
772k 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,...
69
votes
11answers
608k views

Uninstall Grub and use Windows bootloader

I have Windows 8 pre-installed and then 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 the ...
63
votes
6answers
374k 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 ...
62
votes
9answers
240k 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 ...
62
votes
4answers
207k 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 ...
62
votes
4answers
34k 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 ...
58
votes
6answers
734k 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 ...
58
votes
6answers
150k 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'...
57
votes
5answers
335k 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 ...
56
votes
1answer
103k 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
2answers
66k 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: ...
54
votes
6answers
230k 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 ...
51
votes
1answer
54k 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?
50
votes
5answers
187k views

How do I safely change grub2 screen resolution?

I did a fresh install of Ubuntu 11.04 on a HP 550 Notebook. But grub2 isn't really fit in the best screen resolution that this Notebook can support (1280x800). How can I do this without using a ...
50
votes
3answers
47k 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?
45
votes
5answers
321k 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. ...
42
votes
15answers
176k 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?
42
votes
3answers
31k 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. ...
41
votes
6answers
326k 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 ...
40
votes
3answers
30k 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 ...
39
votes
6answers
84k 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.
39
votes
8answers
227k views

How can I edit my Grub bootloader entries (Hide, Rename, Remove)? Preferably doing it manually, and not with a program

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 ...
38
votes
8answers
188k views

I can't get grub menu to show up during boot

After trying (and failing) to install better ATI drivers in 11.10, I've somehow lost my grub menu at boot time. The screen does change to the familiar purple colour, but instead of a list of boot ...
38
votes
8answers
186k views

How do I burn the Windows 10 ISO to a USB?

I did the dd method and it wrote the iso to the USB drive, but I'm not sure that's all I have to do because it is Windows and may not have GRUB and I'm not sure so I'm asking the experts. winusb ...
37
votes
6answers
56k views

How to change the purple background color in grub?

How to do this manually, not installing any tools?
37
votes
5answers
18k views

Decrease GRUB timeout

The GRUB timeout is 8 seconds. Can this be turned down to 2 or 3 seconds? What is the best way to do this?
36
votes
1answer
239k views

How do I boot into recovery mode?

I recently tried booting into the Grub2's menu entry "Ubuntu GNU/Linux, with Linux 3.2.0-24-generic-pae (Recovery Mode) just to see what was there. It booted successfully, but I had no idea what to ...
35
votes
7answers
182k views

What to do when I get an “attempt to read or write outside of disk 'hd0'” error and Boot Repair does not solve the problem?

I tried to install Xubuntu 13.10 on an older computer. I noticed some difficulties during installation that may be relevant to my problems. Notably: The screen resolution was extremely low. The ...
34
votes
8answers
47k views

How to reboot into Windows from Ubuntu?

I'm looking for a way to reboot into Windows from Ubuntu on a 10.10/Vista dual boot system. The specific use case is that I would like to be able to ssh into my running Ubuntu instance and issue a ...