Live Mail ALWAYS Opens Maximized

Try the following (it worked for me) :
(1). Just click the upright button with the 2 orthogones (the middle one between 'Minimize' button and 'Close' button), to have finally the ONE Orthogon set there.
(2). Then Drag the WLM window from the Capture bar (the blue one at the top of the window) towards down and left.
(3). Using your mouse at the right vertical edge of the window, adjust the window's size to make it smaller.
(4). Arrange the window's size as you like and exit WLM 2011.

Next time you will open a received or sent e-mail the size of the window will be the one that you have sized.

I know this is an old thread, but I had exactly this problem - until today.
Like appyface, I have a non-standard screen size/resolution, so that may be a factor.
Anyway, whilst messing around with Properties, I found a solution:

In the Compatibility tab, tick the box to run in compatibility mode, then set it for Windows 7.

No idea why this works, but it did for me.