I have read and followed the documentation "Upgrading An Orchard Site In-Place" carefully.
Tested on two instancies on local computer (IIS and IIS Express)...
"localhost:52336/onneredsbatlag/Admin" and "localhost/onneredsbatlag/Admin" both gives the could not find... - server error HTTP 404.
An extensive log displays ie:
"A tenant could not be started: Default"
"Error loading extension 'Orchard.Localization'"
"Error while loading extension 'Orchard.Messaging'"
New installation from download on local computer works perfectly.
What am I doing wrong ??