GRUB still showing windows 7 boot instead of windows 10

Solution 1:

you have dual boot system in which you are using ubuntu grub . you have upgraded window but ubuntu system grub don't know about your change . it is simply searching in particular disk that you assign and loading window . so you have to change manually in grub.cfg file . open terminal in ubuntu and run command sudo gedit /boot/grub/grub.cfg . here you need to search entry like:

menuentry “Windows 7 (on /dev/sda1)” {
insmod ntfs
set root=’(hd0,1)’

change Window 7 to window 10 or whatever name you want to give and save file and restart system next time you will see change .

Solution 2:

You can try manually editing the Grub file to rename the Microsoft instance from 7 to 10.

sudo gedit /boot/grub/grub.cfg