diff --git a/cell.go b/cell.go
index 229267fc..f455edff 100644
--- a/cell.go
+++ b/cell.go
@@ -288,16 +288,19 @@ func setCellDuration(value time.Duration) (t string, v string) {
 // SetCellInt provides a function to set int type value of a cell by given
 // worksheet name, cell reference and cell value.
 func (f *File) SetCellInt(sheet, cell string, value int) error {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	c, col, row, err := ws.prepareCell(cell)
 	if err != nil {
 		return err
 	}
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	c.S = ws.prepareCellStyle(col, row, c.S)
 	c.T, c.V = setCellInt(value)
 	c.IS = nil
@@ -314,16 +317,19 @@ func setCellInt(value int) (t string, v string) {
 // SetCellBool provides a function to set bool type value of a cell by given
 // worksheet name, cell reference and cell value.
 func (f *File) SetCellBool(sheet, cell string, value bool) error {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	c, col, row, err := ws.prepareCell(cell)
 	if err != nil {
 		return err
 	}
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	c.S = ws.prepareCellStyle(col, row, c.S)
 	c.T, c.V = setCellBool(value)
 	c.IS = nil
@@ -351,16 +357,19 @@ func setCellBool(value bool) (t string, v string) {
 //	var x float32 = 1.325
 //	f.SetCellFloat("Sheet1", "A1", float64(x), 2, 32)
 func (f *File) SetCellFloat(sheet, cell string, value float64, precision, bitSize int) error {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	c, col, row, err := ws.prepareCell(cell)
 	if err != nil {
 		return err
 	}
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	c.S = ws.prepareCellStyle(col, row, c.S)
 	c.T, c.V = setCellFloat(value, precision, bitSize)
 	c.IS = nil
@@ -377,16 +386,19 @@ func setCellFloat(value float64, precision, bitSize int) (t string, v string) {
 // SetCellStr provides a function to set string type value of a cell. Total
 // number of characters that a cell can contain 32767 characters.
 func (f *File) SetCellStr(sheet, cell, value string) error {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	c, col, row, err := ws.prepareCell(cell)
 	if err != nil {
 		return err
 	}
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	c.S = ws.prepareCellStyle(col, row, c.S)
 	if c.T, c.V, err = f.setCellString(value); err != nil {
 		return err
@@ -558,8 +570,6 @@ func (c *xlsxC) getCellDate(f *File, raw bool) (string, error) {
 // intended to be used with for range on rows an argument with the spreadsheet
 // opened file.
 func (c *xlsxC) getValueFrom(f *File, d *xlsxSST, raw bool) (string, error) {
-	f.mu.Lock()
-	defer f.mu.Unlock()
 	switch c.T {
 	case "b":
 		return c.getCellBool(f, raw)
@@ -596,16 +606,19 @@ func (c *xlsxC) getValueFrom(f *File, d *xlsxSST, raw bool) (string, error) {
 // SetCellDefault provides a function to set string type value of a cell as
 // default format without escaping the cell.
 func (f *File) SetCellDefault(sheet, cell, value string) error {
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
 	c, col, row, err := ws.prepareCell(cell)
 	if err != nil {
 		return err
 	}
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	c.S = ws.prepareCellStyle(col, row, c.S)
 	c.setCellDefault(value)
 	return f.removeFormula(c, ws, sheet)
@@ -1264,8 +1277,6 @@ func (ws *xlsxWorksheet) prepareCell(cell string) (*xlsxC, int, int, error) {
 	}
 
 	ws.prepareSheetXML(col, row)
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	return &ws.SheetData.Row[row-1].C[col-1], col, row, err
 }
 
diff --git a/cell_test.go b/cell_test.go
index b3954788..89ec1733 100644
--- a/cell_test.go
+++ b/cell_test.go
@@ -65,7 +65,7 @@ func TestConcurrency(t *testing.T) {
 			// Concurrency iterate columns
 			cols, err := f.Cols("Sheet1")
 			assert.NoError(t, err)
-			for rows.Next() {
+			for cols.Next() {
 				_, err := cols.Rows()
 				assert.NoError(t, err)
 			}
diff --git a/col.go b/col.go
index dd50fb47..e396005b 100644
--- a/col.go
+++ b/col.go
@@ -257,10 +257,13 @@ func (f *File) GetColVisible(sheet, col string) (bool, error) {
 	if err != nil {
 		return true, err
 	}
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return false, err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 	if ws.Cols == nil {
@@ -428,20 +431,24 @@ func (f *File) SetColStyle(sheet, columns string, styleID int) error {
 	if err != nil {
 		return err
 	}
+	f.mu.Lock()
 	s, err := f.stylesReader()
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	ws, err := f.workSheetReader(sheet)
+	if err != nil {
+		f.mu.Unlock()
+		return err
+	}
+	f.mu.Unlock()
 	s.mu.Lock()
 	if styleID < 0 || s.CellXfs == nil || len(s.CellXfs.Xf) <= styleID {
 		s.mu.Unlock()
 		return newInvalidStyleID(styleID)
 	}
 	s.mu.Unlock()
-	ws, err := f.workSheetReader(sheet)
-	if err != nil {
-		return err
-	}
 	ws.mu.Lock()
 	if ws.Cols == nil {
 		ws.Cols = &xlsxCols{}
@@ -484,10 +491,13 @@ func (f *File) SetColWidth(sheet, startCol, endCol string, width float64) error
 	if width > MaxColumnWidth {
 		return ErrColumnWidth
 	}
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 	col := xlsxCol{
@@ -659,10 +669,13 @@ func (f *File) GetColStyle(sheet, col string) (int, error) {
 	if err != nil {
 		return styleID, err
 	}
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return styleID, err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 	if ws.Cols != nil {
@@ -682,10 +695,13 @@ func (f *File) GetColWidth(sheet, col string) (float64, error) {
 	if err != nil {
 		return defaultColWidth, err
 	}
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return defaultColWidth, err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 	if ws.Cols != nil {
diff --git a/excelize.go b/excelize.go
index 2c75f1f0..6c7ce2a1 100644
--- a/excelize.go
+++ b/excelize.go
@@ -234,8 +234,6 @@ func (f *File) setDefaultTimeStyle(sheet, cell string, format int) error {
 // workSheetReader provides a function to get the pointer to the structure
 // after deserialization by given worksheet name.
 func (f *File) workSheetReader(sheet string) (ws *xlsxWorksheet, err error) {
-	f.mu.Lock()
-	defer f.mu.Unlock()
 	var (
 		name string
 		ok   bool
diff --git a/numfmt.go b/numfmt.go
index b5c81bf8..cad67a2d 100644
--- a/numfmt.go
+++ b/numfmt.go
@@ -948,10 +948,13 @@ func (nf *numberFormat) zeroHandler() string {
 // textHandler will be handling text selection for a number format expression.
 func (nf *numberFormat) textHandler() (result string) {
 	for _, token := range nf.section[nf.sectionIdx].Items {
+		if inStrSlice([]string{nfp.TokenTypeDateTimes, nfp.TokenTypeElapsedDateTimes}, token.TType, false) != -1 {
+			return nf.value
+		}
 		if token.TType == nfp.TokenTypeLiteral {
 			result += token.TValue
 		}
-		if token.TType == nfp.TokenTypeTextPlaceHolder || token.TType == nfp.TokenTypeZeroPlaceHolder {
+		if token.TType == nfp.TokenTypeGeneral || token.TType == nfp.TokenTypeTextPlaceHolder || token.TType == nfp.TokenTypeZeroPlaceHolder {
 			result += nf.value
 		}
 	}
diff --git a/numfmt_test.go b/numfmt_test.go
index 51ee8e21..773fac32 100644
--- a/numfmt_test.go
+++ b/numfmt_test.go
@@ -1008,4 +1008,12 @@ func TestNumFmt(t *testing.T) {
 		result := format(item[0], item[1], false, CellTypeNumber)
 		assert.Equal(t, item[2], result, item)
 	}
+	for _, item := range [][]string{
+		{"1234.5678", "General", "1234.5678"},
+		{"1234.5678", "yyyy\"年\"m\"月\"d\"日\";@", "1234.5678"},
+		{"1234.5678", "0_);[Red]\\(0\\)", "1234.5678"},
+	} {
+		result := format(item[0], item[1], false, CellTypeSharedString)
+		assert.Equal(t, item[2], result, item)
+	}
 }
diff --git a/picture.go b/picture.go
index 714f88a5..6ee83595 100644
--- a/picture.go
+++ b/picture.go
@@ -212,10 +212,13 @@ func (f *File) AddPictureFromBytes(sheet, cell string, pic *Picture) error {
 		return err
 	}
 	// Read sheet data.
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
+	f.mu.Unlock()
 	ws.mu.Lock()
 	// Add first picture for given sheet, create xl/drawings/ and xl/drawings/_rels/ folder.
 	drawingID := f.countDrawings() + 1
@@ -591,10 +594,13 @@ func (f *File) GetPictures(sheet, cell string) ([]Picture, error) {
 	}
 	col--
 	row--
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return nil, err
 	}
+	f.mu.Unlock()
 	if ws.Drawing == nil {
 		return nil, err
 	}
diff --git a/sheet.go b/sheet.go
index d80d057e..8d441dd4 100644
--- a/sheet.go
+++ b/sheet.go
@@ -1843,8 +1843,6 @@ func (f *File) relsReader(path string) (*xlsxRelationships, error) {
 // row to accept data. Missing rows are backfilled and given their row number
 // Uses the last populated row as a hint for the size of the next row to add
 func (ws *xlsxWorksheet) prepareSheetXML(col int, row int) {
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
 	rowCount := len(ws.SheetData.Row)
 	sizeHint := 0
 	var ht *float64
@@ -1878,9 +1876,7 @@ func fillColumns(rowData *xlsxRow, col, row int) {
 }
 
 // makeContiguousColumns make columns in specific rows as contiguous.
-func makeContiguousColumns(ws *xlsxWorksheet, fromRow, toRow, colCount int) {
-	ws.mu.Lock()
-	defer ws.mu.Unlock()
+func (ws *xlsxWorksheet) makeContiguousColumns(fromRow, toRow, colCount int) {
 	for ; fromRow < toRow; fromRow++ {
 		rowData := &ws.SheetData.Row[fromRow-1]
 		fillColumns(rowData, colCount, fromRow)
diff --git a/styles.go b/styles.go
index 05f641d8..db7b5609 100644
--- a/styles.go
+++ b/styles.go
@@ -2004,10 +2004,13 @@ func (f *File) NewStyle(style *Style) (int, error) {
 	if fs.DecimalPlaces == 0 {
 		fs.DecimalPlaces = 2
 	}
+	f.mu.Lock()
 	s, err := f.stylesReader()
 	if err != nil {
+		f.mu.Unlock()
 		return cellXfsID, err
 	}
+	f.mu.Unlock()
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	// check given style already exist.
@@ -2131,10 +2134,13 @@ func (f *File) getStyleID(ss *xlsxStyleSheet, style *Style) (int, error) {
 // format by given style format. The parameters are the same with the NewStyle
 // function.
 func (f *File) NewConditionalStyle(style *Style) (int, error) {
+	f.mu.Lock()
 	s, err := f.stylesReader()
 	if err != nil {
+		f.mu.Unlock()
 		return 0, err
 	}
+	f.mu.Unlock()
 	fs, err := parseFormatStyleSet(style)
 	if err != nil {
 		return 0, err
@@ -2179,7 +2185,9 @@ func (f *File) SetDefaultFont(fontName string) error {
 		return err
 	}
 	font.Name.Val = stringPtr(fontName)
+	f.mu.Lock()
 	s, _ := f.stylesReader()
+	f.mu.Unlock()
 	s.Fonts.Font[0] = font
 	custom := true
 	s.CellStyles.CellStyle[0].CustomBuiltIn = &custom
@@ -2188,6 +2196,8 @@ func (f *File) SetDefaultFont(fontName string) error {
 
 // readDefaultFont provides an un-marshalled font value.
 func (f *File) readDefaultFont() (*xlsxFont, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
 	s, err := f.stylesReader()
 	if err != nil {
 		return nil, err
@@ -2803,22 +2813,25 @@ func (f *File) SetCellStyle(sheet, hCell, vCell string, styleID int) error {
 
 	vColIdx := vCol - 1
 	vRowIdx := vRow - 1
-
+	f.mu.Lock()
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
+		f.mu.Unlock()
 		return err
 	}
-	ws.prepareSheetXML(vCol, vRow)
-	makeContiguousColumns(ws, hRow, vRow, vCol)
+	s, err := f.stylesReader()
+	if err != nil {
+		f.mu.Unlock()
+		return err
+	}
+	f.mu.Unlock()
+
 	ws.mu.Lock()
 	defer ws.mu.Unlock()
 
-	s, err := f.stylesReader()
-	if err != nil {
-		return err
-	}
-	s.mu.Lock()
-	defer s.mu.Unlock()
+	ws.prepareSheetXML(vCol, vRow)
+	ws.makeContiguousColumns(hRow, vRow, vCol)
+
 	if styleID < 0 || s.CellXfs == nil || len(s.CellXfs.Xf) <= styleID {
 		return newInvalidStyleID(styleID)
 	}