In order to deploy your UWP apps, you need to activate the developer mode in Windows 10 Settings, but what if your computer refuses to activate this mode?
If this issue happens on your corporate computer, the odds are very high that the cause of your problem is Windows Update itself.
Enterprises can manage themselves Windows updates with a local mirror, it’s what we call Windows Server Update Services (WSUS), instead of downloads updates from Microsoft servers, your corporate computer will download them from a local cache mirror managed by your IT team.
The problem is that the package to install the developer mode can miss on these servers and Windows falls to download it.
How to fix this issue?
The easiest solution is to temporary disable the local WSUS and instead rely on the real Windows Update service.
For that, open regedit.exe and set:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\UseWUServer to 0.
‼ If this key doesn’t exist or was not set to 1, the reason of your error was not this one. Sorry!
Once done, you should restart the Windows Update service, launch cmd.exe with admin rights (right click on cmd.exe, run as administrator) and type:
net stop wuauserv
net start wuauserv
It will restart the Windows Update service, taking into account your new settings! Try to activate again the developer mode and it should work!
One more step, you should reset your Windows Update service to its corporate behavior. Set again UseWUServer to 1 and relaunch the Windows Update service with the same commands that before.