This is a complicated process that, if performed incorrectly, may leave your Windows partition un-bootable. We encourage you to visit the IT Helpdesk for help if you are looking to remove a dual-boot partition. If you decide to do this on your own, please follow exactly the steps in this guide. And remember - always keep your data backed up!

The first thing you must determine is whether your machine is booting with Legacy BIOS or UEFI. To do this, reboot your machine, and go to Setup by hitting F2 when the Dell logo appears. Then, go to Boot Sequence, and make note if you have UEFI or Legacy checked. Follow the appropriate guide below.

• Obtain a Windows installer key on a USB drive
  • For more information, see here: https://www.microsoft.com/en-us/software-download/windows10
• Ensure that your Windows system has fast startup disabled
  • Go to Control Panel → Hardware and Sound → Power Options → Change what the power buttons do
  • Uncheck the fast startup box
  • You may have to select Change Settings that are Currently Unavailable to access the fast startup option
• With your computer off, plug the Windows installer USB into a port
• Turn your computer on. As soon as you see the Dell logo, press the F12 button to open up boot options
• Select your USB device on the list of legacy options and press enter to boot to it
• On the window that opens asking about language preferences, click Next
• You should have a window that asks if you want to install Windows – in the lower left in small text it should say “Repair your computer”, click that text
• Click on the Troubleshoot option
• Click on the Command Prompt option
• Type “bootrec.exe /fixmbr”
• You can then close the window and restart your computer
• It should now boot automatically to Windows
• Go to disk management and remove the disk partitions that were a part of Ubuntu
• After they have been removed right click the main Windows drive and select “extend volume”
• Extend the volume by the full amount to let windows take up the space that was before occupied by Ubuntu
• Follow the steps below to remove grub

• Press the Windows key and type cmd
• The first option listed should be “Command Prompt”, right click and select “Run as administrator”
• Add windows boot manager as a UEFI boot entry with “bcdedit /set ”{bootmgr}“ path \efi\microsoft\boot\bootmgfw.efi”
• Reboot and hit F2 to get into Setup
• Reorder Windows Boot to the top
  • In the right hand plane, there should be a list of boot options that include ubuntu and Onboard NIC
  • In this plane, click on the Windows Boot Manager (it may be called something starting with UEFI) to highlight it, then use the arrows on the side to move it up to the top of the list
• Boot to windows, go to disk management, and remove the disk partitions that were a part of Ubuntu
• After they have been removed right click the main Windows drive and select “extend volume”
• Extend the volume by the full amount to let windows take up the space that was before occupied by Ubuntu
• Follow the steps below to remove grub
• Remove the UEFI Ubuntu boot option from the bios settings under the boot sequence tab

Instructions adapted from here: http://linuxbsdos.com/2015/09/05/how-to-delete-grub-files-from-a-boot-efi-partition-in-windows-10/.

• Run command prompt as an administrator
• Run the following commands:

These commands are used to identify and select the hard drive

• diskpart
• list disk
• sel disk 0

These commands are used to list the partitions, select the Boot EFI partition, then assign it a drive letter

• list vol
• sel vol 2
• assign letter=Z:
• exit

These commands are used to change into the Boot EFI folder and delete the GRUB folder

• Z:
• dir
• dir EFI
• cd EFI
• dir
• rmdir /s Ubuntu
• When prompted if you want to remove ubuntu, enter y