diff --git a/lib.go b/lib.go
index e01c305..08ce248 100644
--- a/lib.go
+++ b/lib.go
@@ -652,11 +652,16 @@ func getRootElement(d *xml.Decoder) []xml.Attr {
 		case xml.StartElement:
 			tokenIdx++
 			if tokenIdx == 1 {
+				var ns bool
 				for i := 0; i < len(startElement.Attr); i++ {
-					if startElement.Attr[i].Value == NameSpaceSpreadSheet.Value {
-						startElement.Attr[i] = NameSpaceSpreadSheet
+					if startElement.Attr[i].Value == NameSpaceSpreadSheet.Value &&
+						startElement.Attr[i].Name == NameSpaceSpreadSheet.Name {
+						ns = true
 					}
 				}
+				if !ns {
+					startElement.Attr = append(startElement.Attr, NameSpaceSpreadSheet)
+				}
 				return startElement.Attr
 			}
 		}
diff --git a/lib_test.go b/lib_test.go
index 7500f49..4895528 100644
--- a/lib_test.go
+++ b/lib_test.go
@@ -289,6 +289,10 @@ func TestBytesReplace(t *testing.T) {
 
 func TestGetRootElement(t *testing.T) {
 	assert.Len(t, getRootElement(xml.NewDecoder(strings.NewReader(""))), 0)
+	// Test get workbook root element which all workbook XML namespace has prefix
+	f := NewFile()
+	d := f.xmlNewDecoder(bytes.NewReader([]byte(`<x:workbook xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main"></x:workbook>`)))
+	assert.Len(t, getRootElement(d), 3)
 }
 
 func TestSetIgnorableNameSpace(t *testing.T) {
diff --git a/pivotTable_test.go b/pivotTable_test.go
index 20528cc..21c2a1d 100644
--- a/pivotTable_test.go
+++ b/pivotTable_test.go
@@ -516,7 +516,7 @@ func TestDeleteWorkbookPivotCache(t *testing.T) {
 	f := NewFile()
 	// Test delete workbook pivot table cache with unsupported workbook charset
 	f.WorkBook = nil
-	f.Pkg.Store("xl/workbook.xml", MacintoshCyrillicCharset)
+	f.Pkg.Store(defaultXMLPathWorkbook, MacintoshCyrillicCharset)
 	assert.EqualError(t, f.deleteWorkbookPivotCache(PivotTableOptions{pivotCacheXML: "pivotCache/pivotCacheDefinition1.xml"}), "XML syntax error on line 1: invalid UTF-8")
 
 	// Test delete workbook pivot table cache with unsupported workbook relationships charset
diff --git a/sheet_test.go b/sheet_test.go
index 47fcd97..89aa507 100644
--- a/sheet_test.go
+++ b/sheet_test.go
@@ -580,7 +580,7 @@ func TestMoveSheet(t *testing.T) {
 
 	// Test move sheet with unsupported workbook charset
 	f.WorkBook = nil
-	f.Pkg.Store("xl/workbook.xml", MacintoshCyrillicCharset)
+	f.Pkg.Store(defaultXMLPathWorkbook, MacintoshCyrillicCharset)
 	assert.EqualError(t, f.MoveSheet("Sheet2", "Sheet1"), "XML syntax error on line 1: invalid UTF-8")
 }
 
diff --git a/slicer_test.go b/slicer_test.go
index 5a79a80..df9e667 100644
--- a/slicer_test.go
+++ b/slicer_test.go
@@ -597,7 +597,7 @@ func TestAddWorkbookSlicerCache(t *testing.T) {
 	// Test add a workbook slicer cache with unsupported charset workbook
 	f := NewFile()
 	f.WorkBook = nil
-	f.Pkg.Store("xl/workbook.xml", MacintoshCyrillicCharset)
+	f.Pkg.Store(defaultXMLPathWorkbook, MacintoshCyrillicCharset)
 	assert.EqualError(t, f.addWorkbookSlicerCache(1, ExtURISlicerCachesX15), "XML syntax error on line 1: invalid UTF-8")
 	assert.NoError(t, f.Close())
 }