If you are using Outlook 2010 with Microsoft Office 365, you must be running the most recent version of Outlook 2010. Please note that this must to be done before moving to Office 365 or before opening Outlook 2010 after moving to Office 365. Follow these steps to ensure that you have the most recent version of Outlook 2010:
- Click File.
- In the left column, click Help.
- In the right column, click Additional Version and Copyright Information.
- An "About Microsoft Outlook" dialog box will open. The first row of information includes two long numbers in parentheses. The first number (next to "Outlook 2010") must be this or higher: 14.0.6126.5003. The second number (next to "SP1 MSO") must be this number or higher: 14.0.6129.5000
- Click OK.
If your numbers are not high enough, follow these steps to update your version of Outlook 2010:
- Close Outlook.
- Click the Windows Start button and navigate to Control Panel.
- If Control Panel is in Category view, click System and Security | Windows Update. If Control Panel is in Icon view, click Windows Update.
- Click Check for updates.
- Follow the instructions for applying updates.
- When the updates have been applied, repeat steps 4 and 5 to see if there are further updates. Continue repeating steps 4 and 5 until you are told there are no further updates.
- Open Outlook 2010 and recheck the version numbers.