Created attachment 22916 [details] The problematic file. Java command executed: java org.apache.poi.poifs.filesystem.POIFSFileSystem test.xls out.xls While reading a Excel file, I'm getting the following exception: Exception in thread "main" java.io.IOException: Invalid header signature; read 4503608217567241, expected -2226271756974174256 at org.apache.poi.poifs.storage.HeaderBlockReader.<init>(HeaderBlockReader.java:112) at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.java:151) at org.apache.poi.poifs.filesystem.POIFSFileSystem.main(POIFSFileSystem.java:415) The test.xls file is attached. The file was received from a Govt organization and there is no way to verify which version of M$ Excel they use. The file opens fine in Excel and openOffice.
The attached file is a BIFF2 file. The only BIFF version POI supports is BIFF8. When you open and re-save with Excel or OO, the file is silently converted to BIFF8. Improved error message added in svn r721620. I am marking this bug as 'WONTFIX' because it would be difficult to extend POI to handle previous BIFF versions.
Created attachment 22963 [details] zip two java files I took a look at the example file (Attachment id=22916) and saw that only 5 BIFF2 records types were present. It was relatively easy to write a BIFF2 stream reader that would handle just these records. This might be a viable solution path if your input stays relatively simple. Here is some sample code to call the attached converter: InputStream is = new FileInputStream("ex46269-22916.xls"); HSSFWorkbook wb = BIFF2To8Converter.convert(is, "Sheet1");