diff --git a/src/ooxml/java/org/apache/poi/POIXMLProperties.java b/src/ooxml/java/org/apache/poi/POIXMLProperties.java
index 307b3d8e5..d7a171912 100644
--- a/src/ooxml/java/org/apache/poi/POIXMLProperties.java
+++ b/src/ooxml/java/org/apache/poi/POIXMLProperties.java
@@ -148,6 +148,9 @@ public class POIXMLProperties {
 			xmlOptions.setSaveSuggestedPrefixes(map);
 
 			OutputStream out = extPart.getOutputStream();
+			if (extPart.getSize() > 0) {
+			    extPart.clear();
+			}
 			ext.props.save(out, xmlOptions);
 			out.close();
 		}
diff --git a/src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java b/src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java
index 5cc894f7d..e210be6f6 100644
--- a/src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java
+++ b/src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java
@@ -599,7 +599,10 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 			throw new IllegalArgumentException("relationshipType");
 		ArrayList<PackagePart> retArr = new ArrayList<PackagePart>();
 		for (PackageRelationship rel : getRelationshipsByType(relationshipType)) {
-			retArr.add(getPart(rel));
+			PackagePart part = getPart(rel);
+			if (part != null) {
+			    retArr.add(part);
+			}
 		}
 		return retArr;
 	}
diff --git a/src/ooxml/java/org/apache/poi/openxml4j/opc/ZipPackage.java b/src/ooxml/java/org/apache/poi/openxml4j/opc/ZipPackage.java
index 9ac8fd17f..a352a8d1f 100644
--- a/src/ooxml/java/org/apache/poi/openxml4j/opc/ZipPackage.java
+++ b/src/ooxml/java/org/apache/poi/openxml4j/opc/ZipPackage.java
@@ -37,7 +37,6 @@ import org.apache.poi.openxml4j.opc.internal.MemoryPackagePart;
 import org.apache.poi.openxml4j.opc.internal.PartMarshaller;
 import org.apache.poi.openxml4j.opc.internal.ZipContentTypeManager;
 import org.apache.poi.openxml4j.opc.internal.ZipHelper;
-import org.apache.poi.openxml4j.opc.internal.marshallers.ZipPackagePropertiesMarshaller;
 import org.apache.poi.openxml4j.opc.internal.marshallers.ZipPartMarshaller;
 import org.apache.poi.openxml4j.util.ZipEntrySource;
 import org.apache.poi.openxml4j.util.ZipFileZipEntrySource;
@@ -444,9 +443,8 @@ public final class ZipPackage extends Package {
                 this.getPartsByRelationshipType(PackageRelationshipTypes.CORE_PROPERTIES_ECMA376).size() == 0    ) {
 				logger.log(POILogger.DEBUG,"Save core properties part");
 
-				// We have to save the core properties part ...
-				new ZipPackagePropertiesMarshaller().marshall(
-                        this.packageProperties, zos);
+				// Add core properties to part list ...
+				addPackagePart(this.packageProperties);
 				// ... and to add its relationship ...
 				this.relationships.addRelationship(this.packageProperties
 						.getPartName().getURI(), TargetMode.INTERNAL,
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
index 2955300e4..34d8eada7 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java
@@ -321,13 +321,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Iterable<X
             }
 
             // Process the named ranges
-            namedRanges = new ArrayList<XSSFName>();
-            if(workbook.isSetDefinedNames()) {
-                for(CTDefinedName ctName : workbook.getDefinedNames().getDefinedNameArray()) {
-                    namedRanges.add(new XSSFName(ctName, this));
-                }
-            }
-
+            reprocessNamedRanges();
         } catch (XmlException e) {
             throw new POIXMLException(e);
         }
@@ -1307,13 +1301,28 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Iterable<X
                 i++;
             }
             names.setDefinedNameArray(nr);
+            if(workbook.isSetDefinedNames()) {
+                workbook.unsetDefinedNames();
+            }
             workbook.setDefinedNames(names);
+                        
+            // Re-process the named ranges
+            reprocessNamedRanges();
         } else {
             if(workbook.isSetDefinedNames()) {
                 workbook.unsetDefinedNames();
             }
         }
     }
+    
+    private void reprocessNamedRanges() {
+        namedRanges = new ArrayList<XSSFName>();
+        if(workbook.isSetDefinedNames()) {
+            for(CTDefinedName ctName : workbook.getDefinedNames().getDefinedNameList()) {
+                namedRanges.add(new XSSFName(ctName, this));
+            }
+        }
+    }
 
     private void saveCalculationChain(){
         if(calcChain != null){
diff --git a/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFBugs.java b/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
index 83623a780..f0266c9f6 100644
--- a/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
+++ b/src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFBugs.java
@@ -17,10 +17,12 @@
 
 package org.apache.poi.xssf.usermodel;
 
+import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -60,6 +62,7 @@ import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.usermodel.WorkbookFactory;
 import org.apache.poi.ss.util.AreaReference;
+import org.apache.poi.ss.util.CellRangeAddress;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.xssf.XSSFITestDataProvider;
 import org.apache.poi.xssf.XSSFTestDataSamples;
@@ -1464,4 +1467,23 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         double rounded = cv.getNumberValue();
         assertEquals(0.1, rounded, 0.0);
     }
+
+    @Test
+    public void bug56468() throws Exception {
+        XSSFWorkbook wb = new XSSFWorkbook();
+        XSSFSheet sheet = wb.createSheet();
+        XSSFRow row = sheet.createRow(0);
+        XSSFCell cell = row.createCell(0);
+        cell.setCellValue("Hi");
+        sheet.setRepeatingRows(new CellRangeAddress(0, 0, 0, 0));
+        
+        ByteArrayOutputStream bos = new ByteArrayOutputStream(8096);
+        wb.write(bos);
+        byte firstSave[] = bos.toByteArray();
+        bos.reset();
+        wb.write(bos);
+        byte secondSave[] = bos.toByteArray();
+        
+        assertThat(firstSave, equalTo(secondSave));
+    }
 }