Installed to USB stick, unable to boot, boot loader not found (Linux Lite 5.4)

[Moltke]

Hi,

I'm trying to install Linux Lite 5.4 to a 32GB USB stick. After installation with no error on a laptop with dual boot Window & Linux MInt 20, I cannot boot into the USB stick on the laptop.
Not only that, I cannot boot into the Linux Mint on the hard drive as well.

Sprintrdriver commented on the tutotial to physically disconnect the internal hard drive before the installation. But I don't want to mess around with the hardware of this laptop.

Well, if you want to install Linux Lite to a USB stick, you will have to follow Sprintdriver's advice. Here's the thing; the problem you're facing is due to the fact that Linux is installing Grub to the internal disk, not the USB, and that's why it didn't boot nor did Linux Mint for the same very reason. The only way to avoid that is to "physically disconnect the internal hard drive before the installation." so the installer doesn't mess with that disk, and grub gets installed in the USB, which is what you need in order to be able to boot Linux Lite from the USB stick.