I am Patrick from France an old Linux user that began with using Slackware distro long time ago. I had a system that was only Linux Mint based. To be able to use some specific applications I needed to install windows 10. I had a HDD available so I unplugged all the disks on my system and plugged only the one on which I will install windows 10. I prepared a USB key ntfs formatted with gpt partition and writed on all files of W10 installation. I proceed to the installation on the new disk. Once the installation done I tested w10 that worked fine and proceed to install all the specific app I needed.
After that: I re-plugged all mint disks and fix the order of boot to the primary of the disks which handle mint 19.3 (master). I booted and have done a update-grub. The result is that the windows 10 disk remains invisible by grub. As I have installed a lot of app on Linux and W10 I wish not to reinstall Mint or W10. I know that this multiboot ubuntu/w10 point have been a lot discussed. Unfortunately I have tested lot of the proposed solutions and none hasn't worked. The W10 disk remains invisible.
Does it exists any efficient solution to fix this problem without destroying all my installations ?
And before is there a way to make a good and complete diagnostic that can orient the solution ?
Thanks by advance. I booted