One common troubleshooting method is to uninstall and reinstall Office or to repair the Office install. While uninstalling and reinstalling rarely fixes the problem (it will only help if the install is corrupt), reinstalling (without uninstalling Office first) will almost always have the same effect as uninstalling and reinstalling: it will either fix the problem or do nothing. Detect and Repair or Office Diagnostics won't fix many problems but also won't harm.
When you use Repair, under most circumstances, your profile and data files are not touched. However, we do recommend making a copy of your *.pst file, just to be safe (and because many users don't have a recent backup of their *.pst file).
Note that you may need your Office CD or installation source available with either Repair or Detect and Repair.
The steps are basically the same for all versions:
- Close Outlook and any other open Office applications
- Open the Control panel
- Find Add or Remove Programs
- Select the Office (or Outlook, if using standalone Outlook)
- Click the Change or Repair button
For the steps and screenshots specific to older versions of Outlook, see:
Outlook 2010, Outlook 2007, Outlook 2003
Office 2013 & Office 2016
Use the Repair process in the Control Panel's Programs and Features. You can open it by typing Add or Remove Programs on the Start screen or in Search. In Windows 10, open the Control Panel then find Programs and Features or Add or Remove Programs.
Quick Repair will check files and replace missing or potentially corrupt files.
Online Repair is essentially a reinstall. User settings and files won't be affected or lost when using Online Repair.
Repair your Office Installation Video Tutorial
See How to Repair Office 2010, 2007, or 2003 Installations for instructions and screenshots for Outlook 2010, Outlook 2007, Outlook 2003.