boot – Kubuntu installed on an external SSD and now I can not load Windows without it

I have a computer running Windows 10. Because I wanted to use an Ubuntu-based operating system, I installed Kubuntu on an external SSD. I have a Lenovo y50-70 laptop, which has a button (next to the power button) that lets you select the hard drive to boot without going directly to the internal hard drive. In the past, I had done it again and I had problems. However, this time, something went wrong.

If the hard drive is connected to my computer at power up, the GRUB menu allows me to select which operating system I want to use. When I have not connected, I receive the following message:

error: no device of this type: 43519df1-eaa6-4ae44-74b9d66931ff.

error: unknown file system.

Entering rescue mode …

grub rescue> _

What I wanted (and what I could do in the past), is that when I start my machine normally (whether I have the hard disk or not), I will start Windows. When I want to use Kubuntu, I have to use the special "Start Menu" (by pressing a button located next to the power button) when connecting the device.

For whatever reason, GRUB has become the default boot system and I do not know how to get the system to go directly to the Windows loader. In order for me to access Windows now, I need to connect my SSD to allow GRUB to be found. How can I fix this?