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Information I've found here suggests that for my system, I need to install 13.04 into an EFI-type partition, since it needs to boot as UEFI. I also understand it is advisable to have only ONE EFI partition on the disk; I've read here that it is OK for Ubuntu and Windows to share the same partition (please confirm). When I try to install into the existing EFI drive, I get the message "No root file system is defined. Please correct from partitioning menu." Do I change the EFI boot partition to another type? Doesn't that defeat the purpose? If I change it to Ext4 Journaling File System, I am given the opportunity to define the '/' Mount point. I haven't proceeded beyond this point for fear I am going to destroy Windows 8 by altering this partition.

BTW, I created three partitions in Windows before installing, per the helpful response to my previous question. But if I try to install into the partition I created for Ubuntu, I get the "No root file system..." error again.

I have read this question/answer several times over:

Much of that answer talks about dealing with Secure Boot - I have already figured out how to disable Secure Boot, so according to that answer "there is no problem" there. If I understand correctly, I want to stay in UEFI with Secure Boot disabled. There is already have an EFI partition, and when I try to install Ubuntu into that EFI partition I get the error message "No root file system is defined. Please correct from partitioning menu." This is my question - and I may be missing something, but I don't see how the question/answer I duplicated helps me with that problem.

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up vote 2 down vote accepted

On an EFI-based computer, the EFI System Partition (ESP) is a FAT partition that holds boot loaders and related files. The firmware reads boot loaders from this partition to boot any OS. Although the EFI spec says that a computer can have multiple ESPs, the Windows installer tends to flake out if there's more than one ESP present, so it's advisable to use just one ESP per computer (or at least per disk; I'm not sure offhand how Windows responds to a two-disk computer when each disk has an ESP). Thus, you should keep your single-ESP configuration. In GParted, parted, and most other libparted-based tools, the ESP is identified as having the "boot flag" set. IIRC, the Ubuntu installer identifies it as an "EFI boot partition." The GPT fdisk (gdisk, cgdisk, and sgdisk) utilities identify the ESP as having a type code of EF00.

Note that you don't install Linux onto the ESP in any meaningful sense. You should create Linux partitions in the normal way on your GPT disk -- say, for swap, /, and /home. In the Ubuntu installer, you then mark the ESP as being the "EFI boot partition." Alternatively, the various automated partitioning options do this automatically.

Whatever you do, do not create a new filesystem on the ESP, and do not remove the "boot flag" from the ESP or set a "boot flag" on any other partition.

Ubuntu has long supported EFI installation and ESPs, and Ubuntu 13.04 is no exception to this rule. This support has been steadily improving, and it's probably better in 13.04 than in previous releases; however, there are still problems. At the moment, Secure Boot is the biggest problem area. Although Ubuntu 13.04 officially supports Secure Boot, there are a lot of problem reports about this combination, so many people prefer to disable Secure Boot in the firmware's setup utility.

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I have disabled Secure Boot. That is not the problem. The problem is when I try to install Ubuntu to the ESP I get the "No root file system..." message. Are you saying I do not install to the ESP, just to the '/', and Ubuntu sees the ESP and uses it? Apologies, but I have very little knowledge and I don't know what GPT fdisk utilities or code EF00 means. @LuisAlvarado – mengelkoch Jul 2 '13 at 22:06
Correct; you do not install Linux to the ESP. Unfortunately, the Ubuntu installer (mis-)labels the ESP as the "EFI boot partition" (a unique term that's not quite the same as the official name). In the installer, you must assign a partition other than the ESP the mount point of / (root). You may also assign mount points to other partitions (/home, /var, and so on), if you so desire. You do not explicitly assign a mount point to the ESP or to the swap partition. – Rod Smith Jul 3 '13 at 0:56
Thank you very much. This clarifies it for me. – mengelkoch Jul 3 '13 at 18:42

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