After an uninstall of Delphi, Nov_2016_Seattle_Update_Subscription_Update.exe does not install anymore but tells that all went well…
It simply does not copy any files because it checks this registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Embarcadero\BDS\17.0\HotfixLevel
And if it is 3 instead of 2 it silently skips the installation.
So set the key HotfixLevel back to 2 and reopen the updater.