I just successfully did an in-place upgrade of Windows 8.1 Enterprise to Windows 10 Enterprise. I was able to do this by creating Windows 10 installation media (generic non-Enterprise edition) onto a USB key and running the setup file in Windows 8.1 Enterprise.
(Note that the tool I used was named MediaCreationTool1903.exe
. I clicked "Download tool now" at Microsoft's "Download Windows 10" page.)
I was actually taking the steps to do a fresh install of Windows 10 Home (because I no longer have an easy way to get an enterprise license), so I was pleasantly surprised to find an in-place upgrade worked without a Windows 10 Enterprise license. So if you're having this issue, I suggest giving the regular Windows 10 installer a try by running it in Windows 8.1 Enterprise.
Note that the official docs on Windows upgrade paths confirm that a Windows 8.1 Enterprise to Windows 10 Enterprise full upgrade is possible, i.e. an upgrade where personal data, settings, and applications are maintained. (One of the comments here was suggesting otherwise.)
Also I don't remember exactly when but I did have a step in the process where the Windows 10 installation media creation tool said "This version of Windows is not supported" or similar, but when I ran the setup file from the USB key, it recognized my enterprise version and offered to upgrade to Windows 10 Enterprise.
Misc. thoughts
I think I was under the impression that this wasn't possible because the "Windows 10 Update Assistant" tool doesn't work on Windows 8.1 Enterprise. I remember that app was saying that "this version of Windows is not supported".
(I'm not sure if this upgrade was always possible. Perhaps it's a recent improvement to the Windows 10 installer.)
(And from what I understand, while the official free upgrade to Windows 10 ended in July 2016, it looks like Microsoft's activation servers still give out digital licenses after upgrading from an earlier Windows version. This page (see "Is Your License Valid") speculates as to why. It doesn't mention Enterprise licenses, but I can confirm that my Windows 10 Enterprise is activated when I upgraded in July 2019. Perhaps even if Upgrade Assistant doesn't work, maybe using the Windows Installer directly is a workaround to updating to Windows 10 for free? It's a bit confusing and I'm not entirely sure, but this is my best guess to explain why it let me upgrade to Windows 10 Enterprise for free.)
1update first to Windows 8.1 (via ISO) and next to Win10 – magicandre1981 – 2015-10-26T05:03:48.580
There is no in-place upgrade path from Windows 8.1 Enterprise to Windows 10 Enterprise. Enterprise versions are licensed independently. – Ramhound – 2015-10-26T10:47:13.990
I'm not worried about the license - I don't mind buying one. I don't want to setup all of my software from scratch - I want to upgrade without reinstalling – Noam – 2015-10-27T05:58:57.623