XL97: Cannot Modify Microsoft Excel 5.0 or 7.0 Add-in

In the Visual Basic Editor, when you attempt to access a project for an add-in saved in the Microsoft Excel 5.0 or 7.0 file format, you receive the following error message: You cannot edit the worksheets or modules in the project, and you cannot modify any of the project properties.

When you run a Microsoft Excel 5.0 or 7.0 add-in in Microsoft Excel 97, the behavior of the add-in remains unchanged. However, the method that you use to edit and protect an add-in in Microsoft Excel 97 is different from the method you use in Microsoft Excel 5.0 or 7.0.

Add-ins that you save in a format for use with earlier versions of Microsoft Excel are protected; you cannot access the worksheets in Microsoft Excel, and you cannot access the modules in the Visual Basic Editor. These protective measures are used to protect the add-in being changed. Microsoft Excel uses a random password to protect the project, which prevents the add-in from being unprotected.

This behavior is by design of Microsoft Excel.

To edit and modify an add-in that is created in Microsoft Excel 5.0 or 7.0, open the source workbook used to create the add-in, and make modifications to the source. After you modify the source workbook, create a new add-in from the source workbook.

For additional information on creating Microsoft Excel 97 add-ins, please see the following article in the Microsoft Knowledge Base: