diff --git a/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java b/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
index dfdf3f92e..8188b0287 100644
--- a/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
+++ b/src/ooxml/java/org/apache/poi/ss/usermodel/WorkbookFactory.java
@@ -208,7 +208,7 @@ public class WorkbookFactory {
         if (POIXMLDocument.hasOOXMLHeader(inp)) {
             return new XSSFWorkbook(OPCPackage.open(inp));
         }
-        throw new IllegalArgumentException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");
+        throw new InvalidFormatException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");
     }
 
     /**
diff --git a/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java b/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
index f3fcbb889..965aa2c3a 100644
--- a/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
+++ b/src/ooxml/testcases/org/apache/poi/ss/TestWorkbookFactory.java
@@ -30,6 +30,7 @@ import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.usermodel.WorkbookFactory;
 import org.apache.poi.util.TempFile;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.poi.openxml4j.opc.OPCPackage;
 
 import junit.framework.TestCase;
@@ -135,7 +136,7 @@ public final class TestWorkbookFactory extends TestCase {
                 stream.close();
             }
             fail();
-        } catch(IllegalArgumentException e) {
+        } catch(InvalidFormatException e) {
             // Good
         }
     }