When opening an Excel .xls (old format) in ProjectWise, you cannot open another “second or third” .xls. No Error message is given. However, you may open a .xlsx, and then open 6 or 7 other .xlsx ProjectWise integrated Excel spreadsheets. This is a known issue.   You may also open a .xls, then open 6 or 7 .xlsx (new format) files in ProjectWise.