14.04 install fails to recognise Win8.1

[pcal]

Hi Guys,

I have a shiny brand new Toshiba Satellite 15.6" L50-B02L laptop that came with Win8.1 on a 1T HDD. I'm advised by the salesman that if I wipe Win8 completely, then I'll be wiping my warranty as well, so I want to dual boot it with an Ubuntu LTS.

I attempted to install 14.04, but the installer failed to recognise that there was an installed OS, and recommended erasing the entire HDD. I selected the "something else" option and checked the drive partition layout. It has several partitions already set up, but the main partition where W8 resides, and the boot partition are fairly obvious. I'm just a little anxious that if I start resizing partitions and setting boot partitions when the installer has failed to recognise the existing OS, that appropriate care may not be taken by the system and I'll end up trashing both Win8.1 and my warranty.

Any suggestions how to guarantee safety for my warranty?

Thanks in anticipation.

Pcal

[leunam12]

Go to google and search for "ubuntu uefi" and read the guides and do a little bit of research first if you haven't done that yet. Next, Back up your hard drive before you attempt to install anything, use Clonezilla and do an entire HDD backup. Then boot Windows 8.1 and press WINDOWS KEY+R and type:
shutdown -s -f -t 00and press ENTER. Then boot your installation media, if Windows 8.1 it's still not recognized use Gparted to resize and create the partitions that you need for Ubuntu and install to that (those) partition(s). Use boot-repair if one of your OS's do not start.

http://clonezilla.org/clonezilla-live/doc/02_Restore_disk_image/advanced/09-advanced-param.php
https://help.ubuntu.com/community/Boot-Repair

[oldfred]

Many useful links are in the link in my signature.

You want to use Windows to shrink the Windows NTFS partition and reboot immediately so it can run chkdsk and make repairs for its new size. Then make sure Windows fast start-up or always on hibernation is off. If UEFI also has a fast boot, turn it off or you may have difficulty getting into UEFI to change settings.
Make full backups. Some with Windows suggest Windows backup tools and some use Clonezilla as leunam12 suggests. Also make sure efi partition is backed up. Or separately back it up to another drive as it is not large.
These are some of the most important links also in link in my signature.
https://help.ubuntu.com/community/UEFI

UEFI install,windows 8 with Something Else screen shots
http://www.everydaylinuxuser.com/2014/05/install-ubuntu-1404-alongside-windows.html

But do not create any partitions with Windows disk tools.
http://www.dedoimedo.com/computers/dual-boot-windows-8-ubuntu.html
https://help.ubuntu.com/community/DiskSpace