Outlook 2010 is a great improvement over Outlook 2007, but is not perfect. When you open Outlook 2010, it will take some time to load depending on the number of new emails it has detected in your inbox. Once Outlook 2010 is running, it will start sending/receiving information which can sometime take forever if you receive large amount of new emails.
If you started Outlook 2010 to perform a quick task like sending an email, check the schedule on calendar, find contacts, or complete the to-do list, then the fastest route is to run it in Offline Mode.
The first step is to go to Send/Receive tab and hit the Cancel All button. Once it has been cancelled, hit the Work Offline button. Now start using Outlook 2010 for the basic tasks. Another benefit of running Outlook 2010 in offline mode is when the email client hangs up due to large amount of data being send and received.
If you have send an email in offline mode, it won’t be send unless you connect to the server again which can be done from within the same tab. There is no switch at the moment which can allow users to start Outlook 2010 in Offline Mode, but I am looking for a hack.