I am 99.999% sure that you did not select "update" but left the default "clean install" option enabled in the 1.2.1 installer.Help! Have upgraded from 1.2.0RC to 1.2.1. Now when I click on MediaPortal.exe - not the shortcut - it loads the configuration program!
Got renamed to _backup.C:\ProgramData\Team MediaPortal
Well, that was pretty dumb of me! Many thanks; all OK now. Apologies.