Unable to open grub

I recently installed Windows 10 along with Ubuntu 19.10 . But when I am starting grub is not showing it is directly opening windows. In bios mode When I changed the boot priority from uefi to legacy, it is directly opening Ubuntu. I don’t know what is happening. Can somebody help with this please? It would be much appreciated

When installing any number of Linux distributions alongside Windows, you have to always first install all non-Linux products and at the very end the Linux product you want to ultimately serve the bootloader with. The reason is that the most recent installation overwrites each previous one. In your case Windows has overwritten what Linux has installed.

What you can do is re-install GRUB2 manually, as stated here or here. You also have a choice on boot repair disks, like these.

Before messing around, create a backup of all important data. I recommend this backup software. Once you have verified the backup has completed successfully, do the GRUB2 reinstallation by following each step in a guide carefully and precisely. Don’t skip steps and don’t skip sentences.

Hi @Akito i installed Windows first then installed Linux.

If these are new installations anyway, the easiest attempt at a solution would be to reinstall everything, following all steps of the installation processes carefully. Additionally, before applying any OS image to your computer, you always have to evaluate its checksum after download, to make sure there were no skipped bytes while the image was downloaded. A lot of unpredictable errors are caused often by corrupted or wrongly burnt images sometimes in addition to already faulty hardware.

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If you installed Ubuntu into legacy mode then it will always go to that first as Windows is always UEFI mode. There is no real need to boot Ubuntu into legacy now as it is capable of running in UEFI mode, I think most distros are now.

If you did not switch off secure boot then that can cause problems, but I take it you read the guide from @abhishek on installing Ubuntu along side windows. It has saved many a poor soul.

In what order did you set the booting. If Windows is first it will always go to that first, if it is Ubuntu it will always go there first. If they are both in the same mode then they will go to the first boot option always.

@Akito has provided you with a more comprehensive answer than I am giving as I did not want to repeat what he said

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it sounds like it might be helpful to find out if both windows and linux are installed in either uefi or bios to make sure they are both the same.

Hi @Akito @ElectricDandySlider thank you. I was making a mistake, I realized that one. I didn’t turn off the secure boot. Now I turned off and reinstalled again. It works completely fine now.
Thank you so much guys.

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