When selecting the appropriate file type for processing Excel documents, SDL Trados Studio looks at the document extension and at the order of the processors available in the File Types list. Because bilingual Excel documents have the same extension as regular Excel documents, (*.xlsx), Studio cannot automatically determine if an Excel file contains bilingual content. As a result, bilingual Excel documents are processed with the first Excel file type processor available in the File Types tree of the Project Settings/Options dialog box.
By default, the Microsoft Excel 2007-2013 file type is located above the Bilingual Excel file type. This means that Studio processes all Excel documents with the generic Excel file type. Therefore, when you are working with bilingual Excel documents, make sure that you manually prioritize the Bilingual Excel file type over the generic Microsoft Excel 2007-2013 file type. For more information, see Why the Order of the File Types List is Important.