Problem partitioning ubuntu as dual boot

Question

I have installed windows 8.1 (64bit), when i try to install ubuntu alongside with windows, it doesn't shows the Alongside windows option, and when we select sometlthing else option, it shows as if the entire disk is unallocated, it doesn't recognize the partitions. Please guide me to partition and install ubuntu along with windows

Answer 1

There are numerous specific possible causes of these symptoms, but my guess is that you installed Windows in BIOS/CSM/legacy mode, which resulted in Windows incompletely converting a GPT disk to MBR form, which has confused libparted, upon which the Ubuntu installer, GParted, parted, and several other tools rely. If I'm right, the simplest solution is to run FixParts (the fixparts program, part of the gdisk package in Ubuntu) on the disk. It should ask if you want to delete the backup GPT data. Respond in the affirmative.

For more on this, see the following:

• The FixParts documentation
• Why is it not showing any partitions?
• GParted shows "unallocated" on my sda drive (parallel boot with Win XP)
• Problems Installing Ubuntu 13.10 Alongside Windows 7 - gpart shows unallocated space
• GParted and Ubuntu installer does not recognize Windows partition, but Ubuntu does
• Lots more questions and answers on this site -- a search will turn them up.