I've first installed Windows 10 and afterwards the latest Xubuntu version. If I boot now it directly boots Xubuntu. Grub won't be loaded. I also changed the boot style in grub from hidden to menu without success. Then I tried to press the esc key during startup to force the grub boot menu without success either. So it looks like grub isn't loaded at all.
When I change the boot order (in UEFI) to the hard disk where windows 10 is installed, it boots without any problems.
I tried out the tool boot-repair. When I chose apply it said that I need to enable legacy mode for CRM. I checked in the UEFI screen and it's already activated. The error I get from boot-repair is LegacyWindows detected.
When installing Xubuntu I created an efi partition as this was required. I see this partition in my fstab. How do I get dual-boot working without having to go into Uefi-Bios to select the disk to boot?
Best Answer
You can't have dual boot between lagacy and uefi systems.
The easiest way to fix that would be to convert Windows boot from Legacy to UEFI mode. There's a step-by-step I found on that how to do that: https://www.maketecheasier.com/convert-legacy-bios-uefi-windows10/
If you want to reinstall windows from fresh iso, you will need to change partition table type using other tools. There's a very good one I've actually used several times before called gdisk: https://www.explorelinux.com/convert-disk-mbr-to-gpt-on-linux/
Before you start - back up your data. If something goes wrong, you'll probably loose everything on that drive.
After you're done run Ubuntua and run grub os-prober to find Windows (in case it was not found automatically). Alternativelly you can install rEFInd boot manager - I find it to be much better than grub for dual-boot efi systems.