Stopping Exchange before restarting a server causes the shutdown to complete much quicker.
net stop MSExchangeMGMT /yes
net stop RESvc /yes
net stop POP3Svc /yes
net stop IMAP4Svc /yes
net stop NntpSvc /yes
net stop SMTPSVC /yes
net stop MSExchangeES /yes
net stop MSExchangeIS /yes
net stop MSExchangeMTA /yes
net stop MSExchangeSA /yes
