I came across this problem after I installed both Debian and Windows 7 system on my laptop. After searching online, I found a solution to this problem. 1. Open /etc/default/grub as root user and make sure the following line is somewhere in the file and uncommented:

    GRUB_DISABLE_OS_PROBER=false

1. Run command update-grub2 and then reboot your computer.

This solution is not just for Windows and Linux dual boot. It is also for dual/multiple Linux operating systems boot.