I don't have a system with UEFI, but from what I know is that when you install linux on an UEFI machine that has windows already installed, then the already existing EFI partition used(except if you have manually do something else while install linux). So, I think that the bootloader is on EFI partition of the machine you installed linux. When you connect the drive in the other machine, the EFI partition on this machine has the required files for windows only. So, probably you need to install grub on the second machine too(so to add the grub file on that EFI partition), or you need to create an EFI boot partition on the external disk and install grub there.2 answer both questions.
Yes windows fast boot has been disabled in the bios.
My machine is a Acer aspire 5 11th gen intel i 5 8gb of ram with a 512gb nvme ssd.
The hard drive is connected through a usb to sata cable.
Yes when i boot into windows the drive is shown in device manager as partitioned.
Model number is: N20C4
This issue has already been solved. But thanks for trying to help!I don't have a system with UEFI, but from what I know is that when you install linux on an UEFI machine that has windows already installed, then the already existing EFI partition used(except if you have manually do something else while install linux). So, I think that the bootloader is on EFI partition of the machine you installed linux. When you connect the drive in the other machine, the EFI partition on this machine has the required files for windows only. So, probably you need to install grub on the second machine too(so to add the grub file on that EFI partition), or you need to create an EFI boot partition on the external disk and install grub there.