Hi, Apologize, I misunderstood what this feature request was for. I judged only based on the feature's title and presumed that the feature was related to the workbook's protection (saving a file as read-only). The feature you are looking for already exists in GemBox.Spreadsheet. When using the following Load method GemBox.Spreadsheet will open a file with FileAccess.Read mode: ExcelFile ef = ExcelFile.Load("Sample.xlsx"); This loading works even if the file is opened by another application. In case you're using another Load method that accepts a stream then you'll need to make sure that the provided stream has the correct access option for your requirements, for example: using (var stream = File.Open("Sample.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) { ExcelFile ef = ExcelFile.Load(stream, LoadOptions.XlsxDefault); // ... } I hope this helps. If the problem remains please submit a support ticket and we'll investigate your issue. Regards, Mario