diff --git a/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.cpp b/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.cpp
index 268bb0db38..b3b74c538c 100644
--- a/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.cpp
+++ b/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.cpp
@@ -55,7 +55,7 @@ namespace BinXlsxRW{
 
 		sMediaPath = pathMediaDir.GetPath();
 	}
-	bool CXlsxSerializer::loadFromFile(CString& sSrcFileName, CString& sDstPath, CString& sXMLOptions, CString& sMediaDir)
+    bool CXlsxSerializer::loadFromFile(const CString& sSrcFileName, const CString& sDstPath, CString& sXMLOptions, CString& sMediaDir)
 	{
 		NSBinPptxRW::CDrawingConverter oOfficeDrawingConverter;
 		oOfficeDrawingConverter.SetMediaDstPath(sMediaDir);
@@ -79,7 +79,7 @@ namespace BinXlsxRW{
 		oBinaryFileReader.ReadFile(sSrcFileName, sDstPath, &oOfficeDrawingConverter, sXMLOptions);
 		return true;
 	}
-	bool CXlsxSerializer::saveToFile(CString& sDstFileName, CString& sSrcPath, CString& sXMLOptions)
+    bool CXlsxSerializer::saveToFile(const CString& sDstFileName, const CString& sSrcPath, CString& sXMLOptions)
 	{
 		COfficeFontPicker* pFontPicker = new COfficeFontPicker();
 		pFontPicker->Init(m_sFontDir);
diff --git a/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.h b/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.h
index f14fae1bf3..f6b89eab68 100644
--- a/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.h
+++ b/ASCOfficeDocxFile2/DocWrapper/XlsxSerializer.h
@@ -28,8 +28,8 @@ namespace BinXlsxRW {
 		
 		void CreateXlsxFolders(CString& sXmlOptions, CString sDstPath,  CString& sMediaPath);
 
-		bool loadFromFile(CString& sSrcFileName, CString& sDstPath, CString& sXMLOptions, CString& sMediaDir);
-		bool saveToFile(CString& sSrcFileName, CString& sDstPath, CString& sXMLOptions);
+        bool loadFromFile(const CString& sSrcFileName, const CString& sDstPath, CString& sXMLOptions, CString& sMediaDir);
+        bool saveToFile(const CString& sSrcFileName, const CString& sDstPath, CString& sXMLOptions);
 		
 		bool loadChart(CString& sChartPath, NSBinPptxRW::CBinaryFileWriter& oBufferedStream, long& lDataSize);
 		bool saveChart(NSBinPptxRW::CBinaryFileReader& oBufferedStream, long lLength, CString& sFilename, CString& sContentTypePath, CString** sContentTypeElement);
@@ -39,4 +39,4 @@ namespace BinXlsxRW {
 		void setDrawingConverter(NSBinPptxRW::CDrawingConverter* pDrawingConverter);
 	};
 }
-#endif	// #ifndef XLSX_SERIALIZER
\ No newline at end of file
+#endif	// #ifndef XLSX_SERIALIZER
diff --git a/XlsxSerializerCom/Reader/BinaryWriter.h b/XlsxSerializerCom/Reader/BinaryWriter.h
index cd8a499171..8584102c70 100644
--- a/XlsxSerializerCom/Reader/BinaryWriter.h
+++ b/XlsxSerializerCom/Reader/BinaryWriter.h
@@ -3299,7 +3299,7 @@ namespace BinXlsxRW {
 		{
 			RELEASEOBJECT(m_oBcw);
 		}
-		void Open(CString& sInputDir, CString& sFileDst, NSFontCutter::CEmbeddedFontsManager* pEmbeddedFontsManager,
+        void Open(const CString& sInputDir, const CString& sFileDst, NSFontCutter::CEmbeddedFontsManager* pEmbeddedFontsManager,
 			NSBinPptxRW::CDrawingConverter* pOfficeDrawingConverter, CString& sXMLOptions)
 		{
 			OOX::CPath path(sFileDst);
diff --git a/XlsxSerializerCom/Reader/CSVReader.cpp b/XlsxSerializerCom/Reader/CSVReader.cpp
index 5ec1036a74..9d06df38a5 100644
--- a/XlsxSerializerCom/Reader/CSVReader.cpp
+++ b/XlsxSerializerCom/Reader/CSVReader.cpp
@@ -49,7 +49,7 @@ namespace CSVReader
 		pCell->m_oRef = OOX::Spreadsheet::CWorksheet::combineRef(nRow, nCol);
 		oRow.m_arrItems.push_back(pCell);
 	}
-    void ReadFromCsvToXlsx(CString &sFileName, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter)
+    void ReadFromCsvToXlsx(const CString &sFileName, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter)
 	{
 		// Создадим Workbook
 		oXlsx.CreateWorkbook();
diff --git a/XlsxSerializerCom/Reader/CSVReader.h b/XlsxSerializerCom/Reader/CSVReader.h
index 7f4a2dae6a..c1e11a4cc6 100644
--- a/XlsxSerializerCom/Reader/CSVReader.h
+++ b/XlsxSerializerCom/Reader/CSVReader.h
@@ -16,7 +16,7 @@
 namespace CSVReader
 {
     void AddCell(CString &sText, INT nStartCell, std::stack<INT> &oDeleteChars, OOX::Spreadsheet::CRow &oRow, INT nRow, INT nCol, bool bIsWrap);
-    void ReadFromCsvToXlsx(CString &sFileName, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter);
+    void ReadFromCsvToXlsx(const CString &sFileName, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter);
 }
 
 #endif //CSV_READER
diff --git a/XlsxSerializerCom/Writer/CSVWriter.cpp b/XlsxSerializerCom/Writer/CSVWriter.cpp
index b619fc8ea5..8792f40d9c 100644
--- a/XlsxSerializerCom/Writer/CSVWriter.cpp
+++ b/XlsxSerializerCom/Writer/CSVWriter.cpp
@@ -55,7 +55,7 @@ namespace CSVWriter
 			nCurrentIndex += nCountChars;
 		}
 	}
-    void WriteFromXlsxToCsv(CString &sFileDst, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter, bool bJSON)
+    void WriteFromXlsxToCsv(const CString &sFileDst, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter, bool bJSON)
 	{
 		NSFile::CFileBinary oFile;
 		oFile.CreateFileW(string2std_string(sFileDst));
diff --git a/XlsxSerializerCom/Writer/CSVWriter.h b/XlsxSerializerCom/Writer/CSVWriter.h
index 939782774a..be5c5aa158 100644
--- a/XlsxSerializerCom/Writer/CSVWriter.h
+++ b/XlsxSerializerCom/Writer/CSVWriter.h
@@ -21,7 +21,7 @@
 namespace CSVWriter
 {
     void WriteFile(NSFile::CFileBinary *pFile, WCHAR **pWriteBuffer, INT &nCurrentIndex, CString &sWriteString, UINT &nCodePage, bool bIsEnd = false);
-    void WriteFromXlsxToCsv(CString &sFileDst, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter, bool bJSON);
+    void WriteFromXlsxToCsv(const CString &sFileDst, OOX::Spreadsheet::CXlsx &oXlsx, UINT nCodePage, const WCHAR wcDelimiter, bool bJSON);
 }
 
 #endif //CSV_WRITER