I may sound like a broken record at times, but the first thing you should do when you encounter quirky Outlook performance issues – including slowness, startup issues and instability – is perform some mail maintenance. This is particularly useful if you have recently installed/uninstalled some Outlook add-ins.
If you haven’t done so lately, I highly recommend that you review my post on Outlook Performance and Mail File Maintenance and take action to archive messages, compact your mail file and run SCANPST against it. A little proactive maintenance here will go a long way towards keeping Outlook snappy. In fact, go ahead and put it as a recurring task on your task list and run through the process every few months. You’ll be glad that you did.