Problem with dual-booting Ubuntu 14.04.2 and Windows 7 x64 Ultimate

Question

I have a very interesting question. Okay, so when I boot Ubuntu 14.04.2 x64 from my USB stick, it doesn't detect Windows 7! I have tried to convert my disk to basic, but I don't seem to have an option for it so I guess I already have a basic one! My computer is custom built so it is NOT UEFI based. When I open Disk Management in Windows 7, there's a green box around my C drive (I have managed to remove it now using a partitioning tool). People have told me that it's because it's a logical partition and I have more than 4 primary, which is wrong. I have 1 (System reserved) which is primary, 1 unallocated for Ubuntu 14.04.2 and my C drive. Is this why Ubuntu is not recognizing my Windows 7 install? I would greatly appreciate any help! !

Answer 1

My computer is custom built so it is NOT UEFI based.

This logic is flawed. Most motherboards introduced since mid-2011 are UEFI-based. Most of these motherboards also provide a Compatibility Support Module (CSM), which is essentially a BIOS emulator -- a CSM enables an EFI-based computer to boot using BIOS-mode boot loaders, much like WINE enables Linux to run Windows binaries. Your system might or might not be using BIOS/CSM/legacy-mode booting for your Windows installation, but if the computer is newer than mid-2011, it almost certainly is UEFI-based.

To determine your Windows boot mode, look at the partition table type. If it uses the Master Boot Record (MBR), the computer is booting in BIOS/CSM/legacy mode; if it uses the newer GUID Partition Table (GPT), it's booting in EFI/UEFI mode. You can check this detail using parted in an Ubuntu installer; open a Terminal and type:

$ sudo parted /dev/sda print | grep Table
Partition Table: gpt

This example shows a GPT disk; an MBR disk will show up as Partition Table: msdos. If parted complains about a missing GPT protective partition (I don't recall the exact wording of this complaint), then you probably have a partition table inconsistency (described later).

As to the main problem, most complaints that the Ubuntu installer "doesn't detect Windows" actually mean that the installer isn't presenting an "install alongside" option. This can happen for any number of reasons, and in most cases you must use the "Something Else" option instead. I recommend you read the following questions and answers:

• "Install alongside" option missing. How do I install Ubuntu beside Windows using "Something Else"?
• How to use manual partitioning during installation?

Note that you should install Ubuntu in the same boot mode (BIOS vs. EFI) as used by Windows. As the Ghostbusters would say, don't cross the streams! You can check the boot mode of the Ubuntu installer by dropping to a shell and looking for a directory called /sys/firmware/efi. If it's present, you've booted in EFI mode; if it's absent, you've booted in BIOS mode.

Another possibility is that your disk uses to use GPT but was converted to use MBR by the Windows installer or some other GPT-unaware tool. In this case, the disk will appear to be completely unpartitioned to the Ubuntu installer. If this is your problem, you must wipe the stray GPT data. This is most easily done with fixparts, which is part of the gdisk package in Ubuntu:

sudo fixparts /dev/sda

See this question and answers or my official FixParts documentation for more details. (I'm the author of FixParts.)

Answer 2

What do you mean green box? can you be more specific? If it is not uefi mode, your disk should be MBR disk, which won't allow you to have more than 4 primary partitions.you will not have the option to convert to basic disk in disk management if it is a dynamic disk unless you delete all volumes on it. You can use third party software, such as AOMEI Partition Assistant, to convert dynamic disk to basic disk without data loss.I think this should be the cause.