hmm.. a maximised window. ok, try this then..
#SingleInstance force
#Persistent
DetectHiddenWindows, On
SendMode, Input
SetTitleMatchMode, 2
appname=NoMin
#d::
IfWinExist, Outlook
WinGet isMax, MinMax, Outlook
Send, #d
If isMax
PostMessage, 0x112, 0xF030,,, Outlook ;maximize
Else
PostMessage, 0x112, 0xF120,,, Outlook ;restore
Return