Dual boot with windows 10 (upgrade from Win 8.1 OEM)

I have dual booted my laptop with windows 8.1 and Ubuntu 15.04. Windows came as a OEM with the laptop so I didn't delete it as I paid for it and I am not using it though. I want to know if I do the free upgrade to Windows 10 will it destroy my Ubuntu partitions? or will it mess up anything in the boot files or grub?

Solution 1:

I just upgraded to Win 10 from Win 7, and the update manager did not bother on touching grub or other partitions. It just upgraded its own partition.

I used the Microsoft Media Creation Tool to upgrade. (I was impatient)

Solution 2:

I think the upgrade will surely replace GRUB and the windows bootloader will not recognize ubuntu so you will have to repair it by booting from ubuntu liveusb and running boot-repair tool. I don't think the ubuntu partition will be affected.