Windows won't boot after installing Ubuntu alongside it
 

Hello!

Originally I had the same problem about a year ago. I followed some guide to dual boot Ubuntu, but Windows refused to boot, caused a lot of problems, and eventually I just abandoned Windows entirely and just installed Ubuntu cleanly on the whole disk. That was on a Dell XPS 9570.

Today, a friend of mine wanted to do the same, on his Dell XPS 9560. We followed this guide, and after a lot of initial hassle (having to set the SATA operation to AHCI instead of "Raid ON", adding nomodeset to the boot settings, altering the boot order, ...) Ubuntu successfully installed, and it works like a charm. Windows, however, does not. Sometimes it goes into a boot loop, all other times it boots into recovery mode, where it's unable to recover successfully, and reboots again. This is very much like the same error I experienced last year, and several bypassers commented how they had had the same issue when trying to dual boot Windows and Ubuntu themselves.

Googling the issue reveals that it is a quite common issue, but none of us have been able to find a solution to the problem.
I solved the problem by abandoning Windows completely, but my friend wants to get Windows working again. The way it is now, with 75% of the disk being reserved for a non-functioning Windows partition is of course just wasteful. I feel Windows and Ubuntu is such a common combination, that this really shouldn't be such an issue.

Afaik, we haven't touched the Windows partitions, so I assume there must be something wrong in the UEFI partition or bootloader..? We also tried changing the boot order, but the problem stays the same regardless of whether it tries to boot straight into Windows, or via GRUB.

Do you have any tips for some Linux newbs such as ourselves? :-)

Thank you so much in advance!

go here, to post boot-info script so we can see what is happening
https://help.ubuntu.com/community/Boot-Repair

Ubuntu has official documentation on dual booting with windows 10 UEFI which has been avaiable on line for years. See the link below and compare that to what you did. THe best bet for help in your circumstances is to use boot repair with the Create BootINfo Summary option. THat will post details on your system and someone should be able to help.

https://help.ubuntu.com/community/UEFI

I'm not shure if this works with Windows and Ubuntu, but I always resolve my problems with dual boot using a MX Linux live usb or CD: you run the usb, click on MX tools and then click on Boot Repair.
Here you'll find four options to repair the GRUB: normally you only needs the first two, Reinstall GRUB bootloader and Repair GRUB configuration file. My advice is trying first to only repair GRUB and if this is not enough, reinstall the bootloader and then repair the GRUB.
This is the MX Linux original link:

https://mxlinux.org/wiki/help-files/...x-boot-repair/

I hope my tip will help you...