In Windows 10, is there a command similar to wuapp.exe that will launch the Windows Update GUI?
Solution 1:
What you're looking for is ms-settings:windowsupdate
From the run dialog this will open the Windows Update settings page. From cmd you need to add start infront of the string (there may be a better way, but I haven't spent much time looking.)
There is a list of all of these strings on MSDN.
Solution 2:
The old Desktop Windows Update UI is removed in Windows 10 . Run ms-settings:windowsupdate to open the Windows Update view from the settings app.