I jumped on the Windows 10 1903 bandwagon. You can see my model number in the subject field. I am a musician, with a requirement for several USB ports. So I also have a D16 dock (with the power supply) and an external monitor (cause father time won't let me see the small print anymore 🙂
I have had some difficulty doing the upgrade, but finally got it to work...mostly. I did an in-place upgrade as I didn't want to go through a very long re-installation process. Listed below is how I got to where I am at the moment:
-first try didn't work. Installation got stuck at 27%. I have the dock (with an external drive attached) and an external drive attached to an internal port. I finally restored to pre-installation state.
-second pass, I disconnected all of my drives, but not the dock. The update installed, but the machine didn't get past the Dell splash screen. I reattached my drives, and used the BIOS to get me to a place where Windows would boot. My taskbar icons were gone and I was unable to pin anything to the taskbar. I rolled the system back again.
-third time...I removed the drive and the dock from the machine and attached the original power supply. The update installed without a hitch and I was able to boot into Windows. I reattached the drive to the internal USB port...all good. I then reattached the Thunderbolt dock and the system got stuck as in the second pass. In an amazing leap of deductive thought (self-deprecating humour there) I got the impression that there was a conflict with the dock.
It was sort of the dock and sort of the Thunderbolt controller. In order to have use of peripherals attached to the dock before Windows booted up, I had to make some changes to the docks and Thunderbolt configuration in the BIOS...as per Dell's info page:
See item 3 BIOS settings. That was great at the time. But it prevented Windows from booting after installing Windows version 1903. So I went into the BIOS to System Configuration > Thunderbolt Adapter Configuration and disabled Enable Thunderbolt Adapter Boot Support and Enable Thunderbolt Adapter Pre-boot Modules. That took care of the problem...or so I thought. My (external) mouse and keyboard receiver is attached to the dock. I had no use of any peripherals attached to the dock until I got into Windows. When I was in Windows, the response from the mouse and keyboard were uneven.
I went back into the BIOS and activated Enable Thunderbolt Adapter Boot Support. The machine would not go past the Dell splash screen. I finally unchecked Enable Thunderbolt Adapter Boot Support and checked Enable Thunderbolt Adapter Pre-boot Modules. The system got me to the Windows boot manager, where I was able to use the mouse attached to the dock to select the updated Windows 10 OS. When I got into Windows, all of the peripherals attached to the dock were functional.
So that is good. However, I am unable to use the mouse, keyboard or access the drive attached to the dock until I get to the Windows boot manager. I am guessing that is a result of the Thunderbolt adapter option I left de-selected in the BIOS.
This where I am now. This is terribly verbose. But I hope that it may help someone else dealing with 1903 upgrade issues, or even those who find they have no use of items attached to the D16 dock until they get to the Windows desktop.
The other reason is I hope someone from Dell support is monitoring this forum. The issue of the Thunderbolt dock, the D16 dock and Windows 1903 was repeated several times until I lucked out with the partial solution. The solutions to get use of the dock before booting into Windows was proposed on the above Dell web page. That now leaves Dell owners having to choose between not being able to boot into Windows, or not having use of items attached to the dock at least until they get to the Windows boot manager, if they have one; or the desktop.
This is not a criticism of Dell. Dell should produce a BIOS and/or driver update to rectify the issue. I did notice that Dell is supporting Windows 10 1903 on the XPS 9550 and even several generations before that....very good!
I didn't post this to make Dell look bad. These are early days. Hopefully this terribly long post has some information that will assist the company in dealing with this issue.
Happy Memorial Day from the wilds of Northern Alberta.