The difference is slight but important. As you suspect it's likely the addins.
A friend of mine is running Windows XP on a P4 system with 1GB of RAM. They are using Outlook 2003. Beginning several days ago, whenever they start Outlook, it tells them that it did not start correctly and gives them the choice to come up in 'safe mode'. If they say 'no' it just loops to the same point. If they say 'yes' it does come up in safe mode. I checked to see if any extensions were disabled by safe mode but there weren't. When we try to exit Outlook, it says that there is a message that has not been sent yet and it attempts to do that without success. The unsent email is to a distribution list. They use the EZ-firewall and EZ-antivirus products as well. If anyone has any suggestions or experiences with this we would appreciate any guidance. Thanks.