Score:0

Windows 10 won't boot or appear in grub

us flag

I just installed ubuntu 20.04 LTS. I installed it onto a second ssd. So I wanted ssd 1 to have windows and ssd 2 to have ubuntu.

Both installations use UEFI but I didn't check that.

When installing ubuntu I pressed "erase disk". The installation went as normal but when I tried to go back into windows it didn't work. after getting the grub menu to show up where was no option for windows. also when I went into the boot options of my motherboard, and then choose the ssd with windows, I just got the grub menu without a windows option. When I look in the disk with ubuntu I can still see all the windows files in the disk(things like program files and other things you would see on the C disk) I already tried using boot-repair, but that didn't do anything at all for me.

So how can I boot into windows again?

edit: link to the bootinfo summary: https://paste.ubuntu.com/p/WZvthjy6SM/

UPDATE: it turns out windows wasn't UEFI. I reinstalled windows but now choosing the uefi version of my usb. after reinstalling windows I also reinstalled ubuntu. and now that both are in uefi mode it works like normal. I could use os-prober to add windows to grub and everything is working now.

ChanganAuto avatar
us flag
UEFI or the old BIOS? Instructions depend on the installation method.
boemgamer avatar
us flag
I think both are UEFI
ChanganAuto avatar
us flag
If so you should be able to select "Windows bootloader manager" at the the UEFI's Boot menu in order to boot Windows directly. Then boot Windows, disable Fast Startup in Windows and shutdown. In the next boot change it back to "Ubuntu" (Grub), boot Ubuntu and run `sudo update-grub`. Windows should now appear in the Grub menu..
boemgamer avatar
us flag
In the boot menu there is no "Windows bootloader manager" option. I only get a list of installed disks. and both the windows and ubuntu ssd bring me to grub.
ChanganAuto avatar
us flag
That's not UEFI mode then.
ChanganAuto avatar
us flag
https://help.ubuntu.com/community/Boot-Repair Please follow instructions (2nd option - from a live session, you can use the same USB you used to install) and at this moment do NOT apply any fix. Instead use "Create a BootInfo summary" and then edit the question and post the resulting report here.
boemgamer avatar
us flag
It should be in the post now
boemgamer avatar
us flag
I didn’t use anlive session so I will benposting a new link soon
boemgamer avatar
us flag
the link is https://paste.ubuntu.com/p/WZvthjy6SM/
oldfred avatar
cn flag
You have newer UEFI system, but Windows installed in old BIOS/MBR configuration. Microsoft has required vendors to install in UEFI/gpt mode since Windows 8 released in 2012. Better to also have Windows in UEFI mode, but install in UEFI mode will convert MBR drive to gpt erasing it. Be sure to backup data. You can use Boot-Repair or your Windows repair/recovery flash drive to install Windows BIOS boot loader to MBR of sda. Do not use Boot-Repair's auto fix as that just installs grub everywhere. Only use Boot-Repair's advaned mode to choose install & MBR.
Score:-1
bo flag

Whenever i have a new OS dual booted, after installation is done, this handy boot-repair tool can be used to purge the current grub and install a fresh one ensuring to fix all boot issues.

Create a boot repair bootable drive from iso above, preferably matching you hdd preferences ie. uefi, mbr, gpt ..etc

Boot to livecd and for good measure ensure you are connected to the network, but either way it should work.

Search for boot-repair, and ensure to purge grub and reinstall, even if you have an already working boot menu.

Also make sure to install new grub bootloader to the first disk, and as long as you don't format it, OSes can be added over and over without issues given you reinstall grub on the first disk always.

...apologies for the answer, probably should be a comment, but still new here .

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