Consider the following scenario. You create a workbook in Microsoft Office Excel 2007, and then you save the workbook in Excel workbook format (.xlsx). One or more cells in the workbook contain a formula that uses the caret (^) operator to mean exponentiation. For example, the workbook contains the following:
You publish the workbook to Excel Services, a feature of Microsoft Office SharePoint Server 2007. In this scenario, Excel Services does not load the workbook when you use a Web browser to try to view the workbook that you published to the server. Instead, you receive the following error message:
Unable to Load Workbook
The workbook that you selected cannot be opened.
The workbook may be in an unsupported file format, or it may be corrupt.
Would you like to try and open this file in Excel?