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I've been running a UEFI boot configuration for a while using GRUB menu, Ubuntu and two copies of Windows 10. To boot to Windows 10 I have to select Windows from the GRUB menu, and then I go to the Windows BCDEdit menu where upon I am asked to select which copy of Windows 10 OS I want.

If I select the first Windows 10 OS, it boots straight into the operating system. However if I select the second Windows OS, it reboots the PC, then I have to select Windows from the GRUB menu again, and then it boots straight into the second Windows OS just fine.

Now I understand this is perfectly normal behaviour with UEFI, but I wonder if there is a way to bypass the GRUB menu only in this second Windows 10 boot scenario nowadays?

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    Is this all on one drive? I have seen where users temporally create a new ESP - EFI system partition and do a Windows repair for one install, so its boot files are in that ESP. UEFI may let you directly boot either, many only want one ESP. But grub does not use UEFI, but looks for Windows boot files in ESP, so can directly boot either Windows. Dual boot two Windows UEFI from grub, two efi partitions. askubuntu.com/questions/653101/boot-repair-windows-not-listed I might keep esp/boot flag on first ESP only, but only have second for time to run Windows repairs. – oldfred Apr 17 at 15:18
  • First of all why do you have 2 windows installations? Secondly, maybe there are multiple copies of the uefi executable on your ESP/Boot folder. You might want to check that, then remove the redundant files, rebuild grub configuration and you should be good to go. – Weezy Apr 17 at 15:38
  • Yes it's all one drive, seperate partitions for each OS instance. I do audio recording (DAW environment), so it's best to keep Windows seperate and not have too many installed applications - it's a perfect solution for me, I've done this for decades and yes I have licenses. Virtual machines solutions apply too much latency. Two EFI partitions may be an idea - thanks... I assume there is no GRUB solution here... – ScriptAlexS Apr 18 at 13:48
  • No, there is no Grub solution because whatever happens to Windows is after Grub. The same probably happens if you set Windows bootloader manager in UEFI (thus bypassing Grub and Ubuntu altogether) and then choosing the same Windows installation from the Windows bootloader menu. It's entirely a Windows problem. And no, you SHOULDN'T have two ESPs in the same drive. – ChanganAuto Apr 18 at 14:08

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