I've installed Elementary as dual boot with Windows 10 but cannot boot Windows 10 using GRUB. It loads fine if I change boot order in my UEFI on motherboard.

Looked at and tried so many solutions here and on the web. Last attempt was using boot-repair. This has made a lot of entries related to Windows but still none work. All that happens when selection a Windows entry is the screen goes black for a few seconds before GRUB menu reappears.

Boot-repair paste is located here: https://paste.ubuntu.com/p/ZtHkfg85yH/.

Any suggestions would be greatly appreciated.

  • Can you paste the contents of /boot/grub.cfg and especially the part with menuentry 'Windows Boot Manager? – qmeeus Dec 18 '19 at 13:11
  • Starting at line 411 is the Windows boot stanza created by os-prober. Line 384 25_custom shows the added entries by Boot-Repair which also can be removed if desired. askubuntu.com/questions/778663/… – oldfred Dec 18 '19 at 15:37

You show Windows is hibernated. That usually is from Windows fast start up. Windows also turns fast start up back on with updates, so even if you turned it off, it may have turned it back on.

Grub only boots working Windows. Or Windows that is not hibernated nor needs chkdsk. In those cases with UEFI you can directly boot Windows from UEFI and fix issue so grub can dual boot again. For occassions when Windows does not boot at all, you should have a Windows repair/recovery flash drive for current version.

Details on how to turn fast start up off.

http://askubuntu.com/questions/843153/ubuntu-16-showing-windows-10-partitions &



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  • Giving this a go tonight - thanks! Assuming that Fast Startup is a Windows 8 & 10 cheat to make it appear faster than previous versions? – AventuraViper Dec 18 '19 at 13:33
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    Microsoft requires UEFI fast boot, which assumes no system changes, so UEFI/BIOS does not have to scan system for hardware & write to drive for operating system. When changing system around, you need that UEFI setting off or you may not have time to press keys to get into UEFI or UEFI boot menu. And then Microsoft requires fast start up which is really just hibernation of boot process. And it often requires vendors to add SSD or tiny SSD as boot cache. All these are to make it seem like Windows boots faster. Well it does boot faster but a lot of kluges. Ubuntu/Linux just boots faster. – oldfred Dec 18 '19 at 13:37
  • Okay, so I booted windows and turned off fast startup. Booted eOS and ran grub-repair. Rebooted and none of the GRUB options for Win10 work still. New paste here post turning off fast starup: paste.ubuntu.com/p/tNpYYvsVT4 – AventuraViper Dec 21 '19 at 7:58
  • Is Secure Boot on. Not sure if grub can boot Windows with UEFI Secure Boot on as it loses chain of "trust". – oldfred Dec 21 '19 at 16:19
  • Secure boot needs a TPM right? My mobo is pre Win8 so secure boot can’t be used. – AventuraViper Dec 21 '19 at 21:50

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