We are hosting the first Scientific Computing Academy at the Physics Department, University of Nairobi. All the training is being done with open source tools, which require step 1 to be installation of a Linux distribution in every participants laptop, or lab computer. We are installing Ubuntu by default since it’s the easiest to manage for such a big group, and most users find it easier to use while transitioning from windows.
So if you want to install a dual boot on your laptop for windows and Ubuntu Linux. You login to your windows, shrink your partition(s) and leave some unallocated space, in which you will create partitions in the Ubuntu installer. Then on restarting the computer and booting from a USB flashdrive/thumbdrive, the installer sees a whole hard drive as unallocated space or a single partition, not recognizing your windows partitions. This is rarely the case with windows 7. It is very common with windows 8, 8.1 and 10. While there are other issues with UEFI and secure boot, this post is specifically about partition tables. Windows installed in UEFI mostly uses GPT partition table.
It is possible that you don’t have MBR partition table with normal, simple/primary or logical partitions. If you have or initially had GPT partition table Gparted doesn’t really get rid of it when you create a new msdos partition table. It is still backed up somewhere in the beginning of your hard drive, so that the Ubuntu installer gets confused.
The solution is to run fixparts in the terminal to fix the parttion tables. If you have residual GPT partition table on the disk, it will ask if you want to delete and write MBR back to the disk. I have done this on two different laptops and it completely fixed the problem and didn’t have to reinstall windows. It can be a subtle problem which is hard to figure out since Gparted doesnt see the residual GPT partition table and windows doesnt seem to understand the difference.
Another issue is have a windows installation on a dynamic drive. For this, you cannot salvage your windows installation. You have to back up your data, delete all the partitions, then convert the drive to simple and then install windows prior to Linux installation.