Unfortunately the post above is true!!!! I had a three year extended warranty and Dell have now replaced the motherboard twice to "fix" the problem with Windows 10. Do not put Windows 10 anywhere near your Dell One!!
The engineer who came to replace the motherboard, memory AND hard drive told me that he had now seen 20 Dell One XPS PCs completely broken - and Windows Update in Windows 10 was the cause. I didn't believe him - how could running an update "fry" the motherboard? But in fact it WAS immediately after the reboot after Windows update that the machine completely died and the motherboard had to be replaced. Twice!
Here's my story.
After installing Windows 10 automatic updates are the new norm. When the machine rebooted it went into a loop of "WPF violation" and "Inaccessible boot drive". Some have suggested that this is to do with Windows update trashing the SSD because of some Intel "go faster" technology. The only way out is to unplug the power lead. The trouble is when you then plug the power in you get nothing other than brief "grey" flash of the screen. No Dell logo. No BIOS access. Nothing other than the relatively silent whir of the fan.
When this happened the first time Dell came on site and replaced the motherboard under my extended warranty. The machine booted into Windows but gave the same "Inaccessible boot device"/"WPF Violation" error blue screen of death that went into a loop. Then, just as before, after the power was disconnected it was dead for good - no Dell logo, no BIOS access.
A second engineer came on site and said everything else on the PC tested fine so it would have to be repaired by Dell themselves (on site engineers are subcontractors). For "next day on site support" this turned out to be a nightmare. I had to wait 4 days for an empty box to be shipped from Germany. Then I had to wait again for UPS to come and collect the PC after I'd phoned them. I was told that Dell would run extensive diagnostics on the box to determine what the real problem was. So it was very disappointing over 2 weeks later to just have the PC returned with a slip of paper saying the motherboard had been replaced (again!)
I think you can guess what happened next. I powered it up. It booted into Windows 10 fine and the world was good. Then Windows Update ran and had a load of new updates requiring a reboot. The machine rebooted and then went into a loop with the error "WPF Violation". Just like the time before I unplugged the power supply and then plugged it back in again and the PC was back to its "dead other than the fan whirring" state.
An engineer came out again and he was the one who told me that WIndows Update was definitely the cause and if I had to have Windows 10 on the PC (I need Windows 10 as I'm a developer and that's our base platform) then to disconnect the PC from the internet and never run Windows Update. That's impractical and unrealistic so I've resigned myself to never being able to run anything other than Windows 8.1 on this oversized piece of junk. I say "piece of junk" because this is by far the worst PC I've ever owned, and has been from day one (when it was delivered with a BIOS error that required talk through on the phone to change settings to get the basic Windows install to work). I know it's only an i5 processor but having to wait 40 seconds after you click on Windows Explorer or 2 minutes for an internet site to show (when you're running 150MB broadband) on a PC that has very little software installed on it is ridiculous.
I'm advising everyone I know to steer well clear of the Dell XPS One. It may look pretty (the screen IS beautiful) but it's a nightmare of a PC, and this latest Windows 10 fiasco is just the last straw.