When opening an Excel workbook that contains square brackets in the name (e.g., "foo"), the user will receive the following error message when attempting to create PivotTables using data from within the workbook:
Data source reference is not valid
The cause is due to square brackets being invalid characters in an Excel workbook file name.
This behavior is expected when these conditions occur. In order to work around this, the user would be required to remove all invalid Excel characters from the file name.
This issue may be seen when trying to open an Excel workbook from Internet Explorer. Internet Explorer creates a copy of the file in the temporary directory, renaming the file with square brackets. This can be avoided by clicking "Save," instead of "Open," when Internet Explorer presents the file to the user.