"Something Happened 0x800704DD - 0x90016"
Came across this error while attempting to download the Windows 10 Installer to a blank USB drive using the Media Creation Tool from Microsoft.
Disregarding the inherent humor involved about how useless this error is for a normal end-user, the solution turned out to be simple:
Scenario: you were logged onto the host machine as a Standard user, you ran the Media Creation Tool, which popped up the request for the local administrators credentials, which you provided. Then you got the error . . .
Solution: Log out of your standard user account, then log in as a local administrator. Run the Media Creation tool and all should be well.
Notes: This goes against the long running advice that I and others have preached for years - don't run your daily usage work as a local admin account, instead set your normal account as a Standard User. But if you followed all the steps of the advice then you created a real admin account for those times you needed to install or update things. That model usually worked from your standard account by entering the credentials for the admin account into the resulting popup window when you launched an installer. Trouble is, even though in this case the popup DID ask for the admin password, the media creation tool broke.
Classic case of Microsoft not playing by their own rules.
Let me know in the comments if this helped, or not - and if not if you found a solution (and please, what that solution was for you.)