One thing that immediately strikes me (and that is different between our setups) is that you have 'Use local database' ticked as repository.
I unselected that when I created this particular workspace, and have my repository somewhere in a cloud, so that when I move between locations (home, office, a nice park in the sun, ...), my charts + analysis + orders + ... travel with me.
Perhaps this is why this excell-kungfu is not working on your end ?
I would suggest a test where you create a new MW-workspace (first window on launch > options > workspaces > New Workspace) and set the repository to a non-standard folder (doesn't have to be in a cloud, just drop it somewhere on your HD, like in your 'Documents'-folder or so) and try again. You would then obviously change the .csv in this new 'config'-folder and add the sectors there.
If it works there, you could move your analysis to this workspace (it's a subfolder you can copy), so you don't lose any work