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!
