Failing to make bootable usb from win10 iso on linux

Solution 1:

There is a tool that will create the correct bootable disk from the ISO : WoeUSB.

If you don't find it in your repository, you may get it via:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt update
sudo apt install woeusb

You will need to format the target disk as follows:

In the Disks application, select the USB on the left, click the hamburger icon, click the Format disk option, select Don’t overwrite existing data (Quick) and Compatible with all systems and devices (MBR/DOS), and then click the Format button.

Launch WoeUSB, and it will automatically detect and select the connected USB drive. Browse to the Windows 10 ISO image and select it. Click on the Install button to begin preparing the bootable Windows 10 USB drive.

If you get the error "Target device is currently busy, unmount all mounted partitions", open Disks, select the USB drive, and then unmount it by clicking the Unmount selected partition icon, and launch WoeUSB again.

More information with screenshots can be found in the article
How To Prepare Windows 10 Bootable USB On Linux.