diff --git a/chart.go b/chart.go
index ae31f71..978a2f9 100644
--- a/chart.go
+++ b/chart.go
@@ -16,6 +16,7 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
+	"path/filepath"
 	"strconv"
 	"strings"
 )
@@ -800,9 +801,11 @@ func (f *File) AddChartSheet(sheet, format string, combo ...string) error {
 	f.addContentTypePart(chartID, "chart")
 	f.addContentTypePart(sheetID, "chartsheet")
 	f.addContentTypePart(drawingID, "drawings")
-	// Update xl/_rels/workbook.xml.rels
-	rID := f.addRels("xl/_rels/workbook.xml.rels", SourceRelationshipChartsheet, fmt.Sprintf("chartsheets/sheet%d.xml", sheetID), "")
-	// Update xl/workbook.xml
+	// Update workbook.xml.rels
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	rID := f.addRels(wbRelsPath, SourceRelationshipChartsheet, fmt.Sprintf("/xl/chartsheets/sheet%d.xml", sheetID), "")
+	// Update workbook.xml
 	f.setWorkbook(sheet, sheetID, rID)
 	chartsheet, _ := xml.Marshal(cs)
 	f.addSheetNameSpace(sheet, NameSpaceSpreadSheet)
diff --git a/excelize.go b/excelize.go
index 0c0f74a..3a511d1 100644
--- a/excelize.go
+++ b/excelize.go
@@ -22,6 +22,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
@@ -112,7 +113,7 @@ func OpenReader(r io.Reader, opt ...Options) (*File, error) {
 		return nil, err
 	}
 	f := newFile()
-	if bytes.Contains(b, oleIdentifier) {
+	if bytes.Contains(b, oleIdentifier) && len(opt) > 0 {
 		for _, o := range opt {
 			f.options = &o
 		}
@@ -345,7 +346,9 @@ func (f *File) AddVBAProject(bin string) error {
 		return errors.New("unsupported VBA project extension")
 	}
 	f.setContentTypePartVBAProjectExtensions()
-	wb := f.relsReader("xl/_rels/workbook.xml.rels")
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	wb := f.relsReader(wbRelsPath)
 	var rID int
 	var ok bool
 	for _, rel := range wb.Relationships {
diff --git a/excelize_test.go b/excelize_test.go
index b0483c7..1b48872 100644
--- a/excelize_test.go
+++ b/excelize_test.go
@@ -201,7 +201,7 @@ func TestCharsetTranscoder(t *testing.T) {
 func TestOpenReader(t *testing.T) {
 	_, err := OpenReader(strings.NewReader(""))
 	assert.EqualError(t, err, "zip: not a valid zip file")
-	_, err = OpenReader(bytes.NewReader(oleIdentifier))
+	_, err = OpenReader(bytes.NewReader(oleIdentifier), Options{Password: "password"})
 	assert.EqualError(t, err, "decrypted file failed")
 
 	// Test open password protected spreadsheet created by Microsoft Office Excel 2010.
diff --git a/lib.go b/lib.go
index 7dcc09e..c89d69f 100644
--- a/lib.go
+++ b/lib.go
@@ -206,7 +206,6 @@ func CoordinatesToCellName(col, row int) (string, error) {
 	if col < 1 || row < 1 {
 		return "", fmt.Errorf("invalid cell coordinates [%d, %d]", col, row)
 	}
-	//Using itoa will save more memory
 	colname, err := ColumnNumberToName(col)
 	return colname + strconv.Itoa(row), err
 }
@@ -244,11 +243,12 @@ func parseFormatSet(formatSet string) []byte {
 // Transitional namespaces.
 func namespaceStrictToTransitional(content []byte) []byte {
 	var namespaceTranslationDic = map[string]string{
-		StrictSourceRelationship:         SourceRelationship.Value,
-		StrictSourceRelationshipChart:    SourceRelationshipChart,
-		StrictSourceRelationshipComments: SourceRelationshipComments,
-		StrictSourceRelationshipImage:    SourceRelationshipImage,
-		StrictNameSpaceSpreadSheet:       NameSpaceSpreadSheet.Value,
+		StrictSourceRelationship:               SourceRelationship.Value,
+		StrictSourceRelationshipOfficeDocument: SourceRelationshipOfficeDocument,
+		StrictSourceRelationshipChart:          SourceRelationshipChart,
+		StrictSourceRelationshipComments:       SourceRelationshipComments,
+		StrictSourceRelationshipImage:          SourceRelationshipImage,
+		StrictNameSpaceSpreadSheet:             NameSpaceSpreadSheet.Value,
 	}
 	for s, n := range namespaceTranslationDic {
 		content = bytesReplace(content, []byte(s), []byte(n), -1)
diff --git a/pivotTable.go b/pivotTable.go
index b7c80c2..3a277c3 100644
--- a/pivotTable.go
+++ b/pivotTable.go
@@ -15,6 +15,7 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
+	"path/filepath"
 	"strconv"
 	"strings"
 )
@@ -138,7 +139,9 @@ func (f *File) AddPivotTable(opt *PivotTableOption) error {
 	}
 
 	// workbook pivot cache
-	workBookPivotCacheRID := f.addRels("xl/_rels/workbook.xml.rels", SourceRelationshipPivotCache, fmt.Sprintf("pivotCache/pivotCacheDefinition%d.xml", pivotCacheID), "")
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	workBookPivotCacheRID := f.addRels(wbRelsPath, SourceRelationshipPivotCache, fmt.Sprintf("/xl/pivotCache/pivotCacheDefinition%d.xml", pivotCacheID), "")
 	cacheID := f.addWorkbookPivotCache(workBookPivotCacheRID)
 
 	pivotCacheRels := "xl/pivotTables/_rels/pivotTable" + strconv.Itoa(pivotTableID) + ".xml.rels"
@@ -661,7 +664,7 @@ func (f *File) getPivotTableFieldNameDefaultSubtotal(name string, fields []Pivot
 	return false, false
 }
 
-// addWorkbookPivotCache add the association ID of the pivot cache in xl/workbook.xml.
+// addWorkbookPivotCache add the association ID of the pivot cache in workbook.xml.
 func (f *File) addWorkbookPivotCache(RID int) int {
 	wb := f.workbookReader()
 	if wb.PivotCaches == nil {
diff --git a/rows.go b/rows.go
index 50e7308..7bbc43d 100644
--- a/rows.go
+++ b/rows.go
@@ -19,7 +19,9 @@ import (
 	"io"
 	"log"
 	"math"
+	"path/filepath"
 	"strconv"
+	"strings"
 )
 
 // GetRows return all the rows in a sheet by given worksheet name (case
@@ -288,7 +290,8 @@ func (f *File) GetRowHeight(sheet string, row int) (float64, error) {
 // after deserialization of xl/sharedStrings.xml.
 func (f *File) sharedStringsReader() *xlsxSST {
 	var err error
-
+	wbPath := f.getWorkbookPath()
+	relPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
 	f.Lock()
 	defer f.Unlock()
 	if f.SharedStrings == nil {
@@ -308,14 +311,14 @@ func (f *File) sharedStringsReader() *xlsxSST {
 			}
 		}
 		f.addContentTypePart(0, "sharedStrings")
-		rels := f.relsReader("xl/_rels/workbook.xml.rels")
+		rels := f.relsReader(relPath)
 		for _, rel := range rels.Relationships {
-			if rel.Target == "sharedStrings.xml" {
+			if rel.Target == "/xl/sharedStrings.xml" {
 				return f.SharedStrings
 			}
 		}
-		// Update xl/_rels/workbook.xml.rels
-		f.addRels("xl/_rels/workbook.xml.rels", SourceRelationshipSharedStrings, "sharedStrings.xml", "")
+		// Update workbook.xml.rels
+		f.addRels(relPath, SourceRelationshipSharedStrings, "/xl/sharedStrings.xml", "")
 	}
 
 	return f.SharedStrings
diff --git a/sheet.go b/sheet.go
index caf87d9..9c9def7 100644
--- a/sheet.go
+++ b/sheet.go
@@ -22,6 +22,7 @@ import (
 	"log"
 	"os"
 	"path"
+	"path/filepath"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -57,9 +58,11 @@ func (f *File) NewSheet(name string) int {
 	f.setContentTypes("/xl/worksheets/sheet"+strconv.Itoa(sheetID)+".xml", ContentTypeSpreadSheetMLWorksheet)
 	// Create new sheet /xl/worksheets/sheet%d.xml
 	f.setSheet(sheetID, name)
-	// Update xl/_rels/workbook.xml.rels
-	rID := f.addRels("xl/_rels/workbook.xml.rels", SourceRelationshipWorkSheet, fmt.Sprintf("worksheets/sheet%d.xml", sheetID), "")
-	// Update xl/workbook.xml
+	// Update workbook.xml.rels
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	rID := f.addRels(wbRelsPath, SourceRelationshipWorkSheet, fmt.Sprintf("/xl/worksheets/sheet%d.xml", sheetID), "")
+	// Update workbook.xml
 	f.setWorkbook(name, sheetID, rID)
 	return f.GetSheetIndex(name)
 }
@@ -89,18 +92,33 @@ func (f *File) contentTypesWriter() {
 	}
 }
 
-// workbookReader provides a function to get the pointer to the xl/workbook.xml
+// getWorkbookPath provides a function to get the path of the workbook.xml in
+// the spreadsheet.
+func (f *File) getWorkbookPath() (path string) {
+	if rels := f.relsReader("_rels/.rels"); rels != nil {
+		for _, rel := range rels.Relationships {
+			if rel.Type == SourceRelationshipOfficeDocument {
+				path = strings.TrimPrefix(rel.Target, string(filepath.Separator))
+				return
+			}
+		}
+	}
+	return
+}
+
+// workbookReader provides a function to get the pointer to the workbook.xml
 // structure after deserialization.
 func (f *File) workbookReader() *xlsxWorkbook {
 	var err error
 	if f.WorkBook == nil {
+		wbPath := f.getWorkbookPath()
 		f.WorkBook = new(xlsxWorkbook)
-		if _, ok := f.xmlAttr["xl/workbook.xml"]; !ok {
-			d := f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML("xl/workbook.xml"))))
-			f.xmlAttr["xl/workbook.xml"] = append(f.xmlAttr["xl/workbook.xml"], getRootElement(d)...)
-			f.addNameSpaces("xl/workbook.xml", SourceRelationship)
+		if _, ok := f.xmlAttr[wbPath]; !ok {
+			d := f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML(wbPath))))
+			f.xmlAttr[wbPath] = append(f.xmlAttr[wbPath], getRootElement(d)...)
+			f.addNameSpaces(wbPath, SourceRelationship)
 		}
-		if err = f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML("xl/workbook.xml")))).
+		if err = f.xmlNewDecoder(bytes.NewReader(namespaceStrictToTransitional(f.readXML(wbPath)))).
 			Decode(f.WorkBook); err != nil && err != io.EOF {
 			log.Printf("xml decode error: %s", err)
 		}
@@ -108,31 +126,28 @@ func (f *File) workbookReader() *xlsxWorkbook {
 	return f.WorkBook
 }
 
-// workBookWriter provides a function to save xl/workbook.xml after serialize
+// workBookWriter provides a function to save workbook.xml after serialize
 // structure.
 func (f *File) workBookWriter() {
 	if f.WorkBook != nil {
 		output, _ := xml.Marshal(f.WorkBook)
-		f.saveFileList("xl/workbook.xml", replaceRelationshipsBytes(f.replaceNameSpaceBytes("xl/workbook.xml", output)))
+		f.saveFileList(f.getWorkbookPath(), replaceRelationshipsBytes(f.replaceNameSpaceBytes(f.getWorkbookPath(), output)))
 	}
 }
 
 // workSheetWriter provides a function to save xl/worksheets/sheet%d.xml after
 // serialize structure.
 func (f *File) workSheetWriter() {
-
-	// optimize memory alloc
 	var arr []byte
 	buffer := bytes.NewBuffer(arr)
 	encoder := xml.NewEncoder(buffer)
-
 	for p, sheet := range f.Sheet {
 		if sheet != nil {
 			for k, v := range sheet.SheetData.Row {
 				f.Sheet[p].SheetData.Row[k].C = trimCell(v.C)
 			}
 			// reusing buffer
-			encoder.Encode(sheet)
+			_ = encoder.Encode(sheet)
 			f.saveFileList(p, replaceRelationshipsBytes(f.replaceNameSpaceBytes(p, buffer.Bytes())))
 			ok := f.checked[p]
 			if ok {
@@ -419,10 +434,12 @@ func (f *File) GetSheetList() (list []string) {
 }
 
 // getSheetMap provides a function to get worksheet name and XML file path map
-// of XLSX.
+// of the spreadsheet.
 func (f *File) getSheetMap() map[string]string {
 	content := f.workbookReader()
-	rels := f.relsReader("xl/_rels/workbook.xml.rels")
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	rels := f.relsReader(wbRelsPath)
 	maps := map[string]string{}
 	for _, v := range content.Sheets.Sheet {
 		for _, rel := range rels.Relationships {
@@ -472,7 +489,9 @@ func (f *File) DeleteSheet(name string) {
 	}
 	sheetName := trimSheetName(name)
 	wb := f.workbookReader()
-	wbRels := f.relsReader("xl/_rels/workbook.xml.rels")
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	wbRels := f.relsReader(wbRelsPath)
 	for idx, sheet := range wb.Sheets.Sheet {
 		if sheet.Name == sheetName {
 			wb.Sheets.Sheet = append(wb.Sheets.Sheet[:idx], wb.Sheets.Sheet[idx+1:]...)
@@ -511,10 +530,11 @@ func (f *File) DeleteSheet(name string) {
 }
 
 // deleteSheetFromWorkbookRels provides a function to remove worksheet
-// relationships by given relationships ID in the file
-// xl/_rels/workbook.xml.rels.
+// relationships by given relationships ID in the file workbook.xml.rels.
 func (f *File) deleteSheetFromWorkbookRels(rID string) string {
-	content := f.relsReader("xl/_rels/workbook.xml.rels")
+	wbPath := f.getWorkbookPath()
+	wbRelsPath := strings.TrimPrefix(filepath.Join(filepath.Dir(wbPath), "_rels", filepath.Base(wbPath)+".rels"), string(filepath.Separator))
+	content := f.relsReader(wbRelsPath)
 	for k, v := range content.Relationships {
 		if v.ID == rID {
 			content.Relationships = append(content.Relationships[:k], content.Relationships[k+1:]...)
diff --git a/xmlDrawing.go b/xmlDrawing.go
index 91b6b59..d2a59e1 100644
--- a/xmlDrawing.go
+++ b/xmlDrawing.go
@@ -33,6 +33,7 @@ var (
 
 // Source relationship and namespace.
 const (
+	SourceRelationshipOfficeDocument             = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument"
 	SourceRelationshipChart                      = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/chart"
 	SourceRelationshipComments                   = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/comments"
 	SourceRelationshipImage                      = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image"
@@ -50,6 +51,7 @@ const (
 	NameSpaceXML                                 = "http://www.w3.org/XML/1998/namespace"
 	NameSpaceXMLSchemaInstance                   = "http://www.w3.org/2001/XMLSchema-instance"
 	StrictSourceRelationship                     = "http://purl.oclc.org/ooxml/officeDocument/relationships"
+	StrictSourceRelationshipOfficeDocument       = "http://purl.oclc.org/ooxml/officeDocument/relationships/officeDocument"
 	StrictSourceRelationshipChart                = "http://purl.oclc.org/ooxml/officeDocument/relationships/chart"
 	StrictSourceRelationshipComments             = "http://purl.oclc.org/ooxml/officeDocument/relationships/comments"
 	StrictSourceRelationshipImage                = "http://purl.oclc.org/ooxml/officeDocument/relationships/image"
diff --git a/xmlWorksheet.go b/xmlWorksheet.go
index 8880909..e5ea60d 100644
--- a/xmlWorksheet.go
+++ b/xmlWorksheet.go
@@ -313,7 +313,7 @@ type xlsxSheetData struct {
 // xlsxRow directly maps the row element. The element expresses information
 // about an entire row of a worksheet, and contains all cell definitions for a
 // particular row in the worksheet.
-type xlsxRow struct {	// alignment word
+type xlsxRow struct { // alignment word
 	C            []xlsxC `xml:"c"`
 	R            int     `xml:"r,attr,omitempty"`
 	Spans        string  `xml:"spans,attr,omitempty"`
@@ -456,7 +456,6 @@ type DataValidation struct {
 //      s (Shared String)         | Cell containing a shared string.
 //      str (String)              | Cell containing a formula string.
 //
-// fixme: how to make this structure smaller; cur size is 152 bytes. it's be too bigger.
 type xlsxC struct {
 	XMLName  xml.Name `xml:"c"`
 	XMLSpace xml.Attr `xml:"space,attr,omitempty"`