When installing Microsoft Office 2010, which Office 2010 Technical Preview version has been released to many beta tester, Office 2010 setup installation wizard will offer to ‘upgrade’ to uninstall and replace or overwrite Office 2007, or any earlier versions of Office suite or applications such as Office 2003 or Office XP with Office 2010.

In order to allow installing of both Office 2010 and Office 2007 (and even Office 2003 or Office XP) side by side together and exist in parallel, Office 2010 has to be installed different directory or folder, so that existing Office 2007 program files don’t get overwritten. Use the following trick to install Office 2010 in addition to Office 2007 so that both applications such as Word, Excel, PowerPoint, Publisher, OneNote, SharePoint and etc can be run simultaneously and concurrently.

  1. Run Office 2010 installation wizard. Select Customize when prompted to choose the preferred type of Office 2010 installation of either “Upgrade” or “Customize”.

    Upgrade or Customize Office 2010 Installation

  2. Click Browse and select another installation folder path for Office 2010 which is not the same with existing Office installation path. For example, C:\Program Files\Microsoft Office 2010\.
  3. The setup will install Office 2010 and retain Office 2007 and any other older versions of Office apps.

Tip: Once Office 2010 is installed, the default program for Office documents, spreadsheets, presentations and other files will be defaulted to Office 2010, but it can be changed manually in Control Panel. A simpler way is to re-run Office 2007 Setup.exe setup wizard, and allow it to repair Office 2007 installation.

Note that although both Office 2010 and Office 2007 can co-exist, Outlook 2007 and Outlook 2010 apparently not. Only one version of Outlook can be installed at any time. Thus, Outlook 2007 will be uninstalled and leaving only Outlook 2010.

End-user who wishes to install Office 2010 without uninstalling Office 2007 can also download the following config.MSP Windows Installer Patch setup customization file which already been configured to keep and retail old Office components and applications.

Download config.MSP for installing Office 2010 without uninstalling or removing Office 2007.

To use the config.MSP to install Office 2007 and keep Office 2007 side by side (not uninstalling Office 2007), copy the downloaded config.MSP to the folder that contains Setup.exe and other installation files for Office 2010, and the run the following command in that folder in an elevated command prompt window (or in Start Search or Run command box).

SETUP /adminfile config.msp

Office 2010 and Office 2007 in Start Menu