Every time I load Excel, an empty box/worksheet pops up as well as an
ordinary usable worksheet. It's just annoying coz I have to close the empty
one every time. It causes no other problems.

I have nothing in the XLSTART folder nor "At startup, open all files in".

The box has only a title bar and up/down scroll bar. No toolbar nor menus.
If I maximize it, it only fills half the screen.
If I right mouse click on the title bar, I get Edit, Default, Properties.
If I select Properties, I get 4 tabs: Options, Font, Layout, Colours.

Any idea what this is and how to stop it popping up?