# Ubuntu – I cannot re-install Ubuntu 15.04 alongside windows 8.1

dual-bootgrub2partitioninguefi

This question may seem repeated but I have other more issues.
I installed 8.1 in my dell 5537 and dual booted it with ubuntu 14.04..I worked well..I installed with alongside windows option..It took 30gb(as I selected the space) space from my logical drive which was last drive…I have four partitions c:,D:,E:,F:(or local drives). Now I deleted the ubuntu from disk management(as there was some problem in ubuntu and i could not fix it).I fixed the windows MBR with live CD. I now want to dual boot ubuntu 15.04 again..I have changed boot mode to UEFI(with secure mode disabled) I get grub to install ubuntu. I clicked install ubuntu. Now i get the Message of

"force UEFI installation?…this machine's firm ware has started the installer in UEFI modebut it looks like there may exist operating systems already installed using "BIOS compatibility mode"…If you wish to install in UEFI mode and dont care about keeping the ability to boot one of the existing system,you have the option to force that here……".

Now if i force UEFI i cannot see any of my partitions of windows and see my whole disk as 500gb disk(as /dev/sda ntfs) and no option of new partition table or other disk…It will erase my whole disk…..I have already shrinked volume from C: and divided that space into 3 part (one primary and active ,two logical).

I use mostly windows and don't want to lose any data from any disk and volumes..

It sounds like you've converted from an EFI/GPT setup to a BIOS/MBR setup, but you did so with a tool that does an incomplete GPT-to-MBR conversion. Thus, you're not really using your EFI/UEFI firmware as such, so the preceding references may seem of only peripheral interest -- but your firmware is an EFI, not a BIOS, and this fact means that you're dealing with EFI issues even when you boot in BIOS/CSM/legacy mode. If I'm right, the fix to your specific problem is to use FixParts (part of the gdisk package in Ubuntu) to remove the stray GPT data. See here for more information: