There seems to be a strange bug when sending keystrokes to DOS programs (e.g. edit.com) running in a CMD.EXE window. It will only send "special" keys and keys with a modifer. For example {ENTER} works fine as does {F2} but the alphabetic and numeric keys don't work unless shift (+) is applied. Everything works fine when sending keys to a GUI app like Notepad.
this: win.TypeKeys("+MI+C+H") # results in 'MCH'
I tried importing directly:
from pywinauto.SendKeysCtypes import SendKeys
SendKeys("+MI+C+H") # This still gives 'MCH'
The latest version of SendKeys v0.3 does not have this bug. I downloaded the Python 2.7 version here: https://bitbucket.org/orutherfurd/sendkeys/issue/5/windows-installer-for-python-27 (see last comment by Charles Duffy).