Error message when you try to start an Office 2008 for Mac program: "Microsoft Office 2008 cannot start because it is already in use"

When you try to start a Microsoft Office 2008 for Mac program, you receive an error message that resembles the following:

This issue occurs when the following conditions are true:

• Office 2008 for Mac is installed on a computer that is connected to a network.
• Another instance of Office 2008 for Mac is running on another computer that is connected to the network.
• The product ID is the same for both instances of Office 2008 for Mac.

When you start an Office 2008 for Mac program, the program sends out a request over the network. The request looks for other Office 2008 for Mac programs that are running on other computers that are connected to the network. If other Office 2008 for Mac programs are running, the programs compare product ID numbers with the requesting program. If any of those product ID numbers match, the requesting program does not start. Additionally, the warning message that is mentioned in the "Symptoms" section appears.

To resolve this issue, you must remove the licensing information for Office 2008 for Mac from one of the computers. Then, enter new and valid licensing information for Office 2008 for Mac on that computer.

To remove the Office 2008 for Mac licensing information and enter the correct information, follow these steps:

1. In Finder, click Go, and then click Applications.
2. Open the Microsoft Office 2008 folder, and then open the Office folder.
3. Drag OfficePID.plist to the Trash.
4. Close all windows.
5. In Finder, click Go, and then click Home.
6. Open the Library folder, open the Preferences folder, and then open the Microsoft folder.
7. Drag the Office 2008 folder to the Trash.
8. Restart Office 2008, and enter a new or unused CD-Key when you are prompted.

Microsoft Office for Mac Standard and Microsoft Office for Mac Media Edition are licensed for use on up to two personal computers (one portable and one desktop) by a single user. Microsoft Office for Mac Home and Student Edition is licensed for use on up to three personal computers in the same household.