diff --git a/PowerEditor/src/MISC/Exception/MiniDumper.cpp b/PowerEditor/src/MISC/Exception/MiniDumper.cpp
index 7ef2cbe6..e63c43b5 100644
--- a/PowerEditor/src/MISC/Exception/MiniDumper.cpp
+++ b/PowerEditor/src/MISC/Exception/MiniDumper.cpp
@@ -54,7 +54,7 @@ bool MiniDumper::writeDump(EXCEPTION_POINTERS * pExceptionInfo)
 		{
 			::GetModuleFileName(NULL, szDumpPath, MAX_PATH);
 			::PathRemoveFileSpec(szDumpPath);
-			lstrcat(szDumpPath, TEXT("\\NppDump.dmp"));
+			wcscat_s(szDumpPath, TEXT("\\NppDump.dmp"));
 
 			// ask the user if they want to save a dump file
 			int msgret = ::MessageBox(NULL, TEXT("Do you want to save a dump file?\r\nDoing so can aid in developing Notepad++."), msgTitle, MB_YESNO);
diff --git a/PowerEditor/src/MISC/RegExt/regExtDlg.cpp b/PowerEditor/src/MISC/RegExt/regExtDlg.cpp
index 8c2b3dbc..884f3195 100644
--- a/PowerEditor/src/MISC/RegExt/regExtDlg.cpp
+++ b/PowerEditor/src/MISC/RegExt/regExtDlg.cpp
@@ -365,7 +365,7 @@ bool RegExtDlg::deleteExts(const TCHAR *ext2Delete)
 	if ((nbValue <= 1) && (!nbSubkey))
 	{
 		TCHAR subKey[32] = TEXT("\\");
-		lstrcat(subKey, ext2Delete);
+		wcscat_s(subKey, ext2Delete);
 		::RegDeleteKey(HKEY_CLASSES_ROOT, subKey);
 	}
 	else
@@ -411,8 +411,9 @@ void RegExtDlg::writeNppPath()
 			TCHAR nppPath[MAX_PATH];
 			::GetModuleFileName(_hInst, nppPath, MAX_PATH);
 
-			TCHAR nppPathParam[MAX_PATH] = TEXT("\"");
-			lstrcat(lstrcat(nppPathParam, nppPath), TEXT("\" \"%1\""));
+			TCHAR nppPathParam[MAX_PATH] = TEXT("\""); 
+			wcscat_s(nppPathParam, nppPath);
+			wcscat_s(nppPathParam, TEXT("\" \"%1\""));
 
 			::RegSetValueEx(hKey, nullptr, 0, REG_SZ, (LPBYTE)nppPathParam, (lstrlen(nppPathParam)+1)*sizeof(TCHAR));
 		}
@@ -432,7 +433,8 @@ void RegExtDlg::writeNppPath()
 			::GetModuleFileName(_hInst, nppPath, MAX_PATH);
 
 			TCHAR nppPathParam[MAX_PATH] = TEXT("\"");
-			lstrcat(lstrcat(nppPathParam, nppPath), TEXT("\",0"));
+			wcscat_s(nppPathParam, nppPath);
+			wcscat_s(nppPathParam, TEXT("\",0"));
 
 			::RegSetValueEx(hKey, nullptr, 0, REG_SZ, (LPBYTE)nppPathParam, (lstrlen(nppPathParam)+1)*sizeof(TCHAR));
 		}
diff --git a/PowerEditor/src/ScitillaComponent/AutoCompletion.cpp b/PowerEditor/src/ScitillaComponent/AutoCompletion.cpp
index 7c4c1d78..cdfe3dd8 100644
--- a/PowerEditor/src/ScitillaComponent/AutoCompletion.cpp
+++ b/PowerEditor/src/ScitillaComponent/AutoCompletion.cpp
@@ -768,9 +768,9 @@ bool AutoCompletion::setLanguage(LangType language) {
 	TCHAR path[MAX_PATH];
 	::GetModuleFileName(NULL, path, MAX_PATH);
 	PathRemoveFileSpec(path);
-	lstrcat(path, TEXT("\\autoCompletion\\"));
-	lstrcat(path, getApiFileName());
-	lstrcat(path, TEXT(".xml"));
+	wcscat_s(path, TEXT("\\autoCompletion\\"));
+	wcscat_s(path, getApiFileName());
+	wcscat_s(path, TEXT(".xml"));
 
 	if (_pXmlFile)
 		delete _pXmlFile;
diff --git a/PowerEditor/src/TinyXml/tinyXmlA/tinystrA.cpp b/PowerEditor/src/TinyXml/tinyXmlA/tinystrA.cpp
index 3640ea72..4b161803 100644
--- a/PowerEditor/src/TinyXml/tinyXmlA/tinystrA.cpp
+++ b/PowerEditor/src/TinyXml/tinyXmlA/tinystrA.cpp
@@ -210,7 +210,6 @@ void TiXmlStringA::append( const char * suffix )
             // strcpy (new_string, cstring);
 
         // append the suffix. It does exist, otherwize we wouldn't be expanding 
-        // strcat (new_string, suffix);
         memcpy (new_string + length (), 
                 suffix,
                 strlen (suffix) + 1);
@@ -226,7 +225,6 @@ void TiXmlStringA::append( const char * suffix )
     else
     {
         // we know we can safely append the new string
-        // strcat (cstring, suffix);
         memcpy (cstring + length (), 
                 suffix, 
                 strlen (suffix) + 1);
diff --git a/PowerEditor/src/TinyXml/tinystr.cpp b/PowerEditor/src/TinyXml/tinystr.cpp
index 45343fda..aa536bfc 100644
--- a/PowerEditor/src/TinyXml/tinystr.cpp
+++ b/PowerEditor/src/TinyXml/tinystr.cpp
@@ -201,7 +201,6 @@ void TiXmlString::append( const TCHAR * suffix )
             memcpy (new_string, cstring, 1 + length ());
 
         // append the suffix. It does exist, otherwize we wouldn't be expanding 
-        // lstrcat (new_string, suffix);
         memcpy (new_string + length (), 
                 suffix,
                 lstrlen (suffix) + 1);
@@ -217,7 +216,6 @@ void TiXmlString::append( const TCHAR * suffix )
     else
     {
         // we know we can safely append the new generic_string
-        // lstrcat (cstring, suffix);
         memcpy (cstring + length (), 
                 suffix, 
                 lstrlen (suffix) + 1);
diff --git a/PowerEditor/src/WinControls/ColourPicker/WordStyleDlg.cpp b/PowerEditor/src/WinControls/ColourPicker/WordStyleDlg.cpp
index 8acc694a..3620b944 100644
--- a/PowerEditor/src/WinControls/ColourPicker/WordStyleDlg.cpp
+++ b/PowerEditor/src/WinControls/ColourPicker/WordStyleDlg.cpp
@@ -744,11 +744,11 @@ void WordStyleDlg::setVisualFromStyleList()
 	if (lbTextLen > styleNameLen)
 		return;
 	::SendDlgItemMessage(_hSelf, IDC_STYLES_LIST, LB_GETTEXT, i, reinterpret_cast<LPARAM>(styleName));
-
-	lstrcat(lstrcat(str, TEXT(" : ")), styleName);
+	wcscat_s(str, TEXT(" : "));
+	wcscat_s(str, styleName);
 
 	// PAD for fix a display glitch
-	lstrcat(str, TEXT("          "));
+	wcscat_s(str, TEXT("          "));
 	colourHooker.setColour(c);
 	::SetWindowText(_hStyleInfoStaticText, str);
 
diff --git a/PowerEditor/src/WinControls/Grid/BabyGrid.cpp b/PowerEditor/src/WinControls/Grid/BabyGrid.cpp
index c68370f4..ebb0a655 100644
--- a/PowerEditor/src/WinControls/Grid/BabyGrid.cpp
+++ b/PowerEditor/src/WinControls/Grid/BabyGrid.cpp
@@ -1186,8 +1186,8 @@ void DisplayEditString(HWND hWnd,int SI, const TCHAR* tstring)
 
        if(lstrlen(BGHS[SI].editstring)<=300)
            {
-            lstrcat(BGHS[SI].editstring,tstring);
-            lstrcpy(BGHS[SI].editstringdisplay,BGHS[SI].editstring);
+		   wcscat_s(BGHS[SI].editstring,tstring);
+		   wcscat_s(BGHS[SI].editstringdisplay,BGHS[SI].editstring);
            }
        else
            {
@@ -1577,16 +1577,16 @@ LRESULT CALLBACK GridProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 			  {
 			   //protecting or unprotecting a cell that isn't in the list
 			   //add it as blank;
-				  lstrcat(buffer, TEXT("|"));
+				  wcscat_s(buffer, TEXT("|"));
 				  if((BOOL)lParam)
 				  {
-				   lstrcat(buffer, TEXT("PA"));
+					  wcscat_s(buffer, TEXT("PA"));
 				  }
 				  else
 				  {
-				   lstrcat(buffer, TEXT("UA"));
+					  wcscat_s(buffer, TEXT("UA"));
 				  }
-				  lstrcat(buffer, TEXT("|"));
+				  wcscat_s(buffer, TEXT("|"));
 				  SendMessage(BGHS[SelfIndex].hlist1, LB_ADDSTRING, FindResult, reinterpret_cast<LPARAM>(buffer));
 			  }
 
@@ -1653,20 +1653,20 @@ LRESULT CALLBACK GridProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 			  }
 
               //now add it
-			  lstrcat(buffer, TEXT("|"));
-			  lstrcat(buffer,BGHS[SelfIndex].protect);
+			  wcscat_s(buffer, TEXT("|"));
+			  wcscat_s(buffer,BGHS[SelfIndex].protect);
               //determine data type (text,numeric, or boolean)(1,2,3)
               //iDataType=DetermineDataType((TCHAR*)lParam);
 
 			  iDataType = 1;
-              if(iDataType==1){lstrcat(buffer, TEXT("A"));}
-              if(iDataType==2){lstrcat(buffer, TEXT("N"));}
-              if(iDataType==3){lstrcat(buffer, TEXT("T"));}
-              if(iDataType==4){lstrcat(buffer, TEXT("F"));}
-			  if(iDataType==5){lstrcat(buffer, TEXT("G"));}
+              if(iDataType==1){ wcscat_s(buffer, TEXT("A"));}
+              if(iDataType==2){ wcscat_s(buffer, TEXT("N"));}
+              if(iDataType==3){ wcscat_s(buffer, TEXT("T"));}
+              if(iDataType==4){ wcscat_s(buffer, TEXT("F"));}
+			  if(iDataType==5){ wcscat_s(buffer, TEXT("G"));}
 
-			  lstrcat(buffer, TEXT("|"));
-              lstrcat(buffer, (TCHAR*)lParam);
+			  wcscat_s(buffer, TEXT("|"));
+			  wcscat_s(buffer, (TCHAR*)lParam);
 			  FindResult = static_cast<int32_t>(SendMessage(BGHS[SelfIndex].hlist1, LB_ADDSTRING, 0, reinterpret_cast<LPARAM>(buffer)));
 
               if(FindResult==LB_ERR)
diff --git a/PowerEditor/src/WinControls/OpenSaveFileDialog/FileDialog.cpp b/PowerEditor/src/WinControls/OpenSaveFileDialog/FileDialog.cpp
index f58bc27b..34a7392b 100644
--- a/PowerEditor/src/WinControls/OpenSaveFileDialog/FileDialog.cpp
+++ b/PowerEditor/src/WinControls/OpenSaveFileDialog/FileDialog.cpp
@@ -244,7 +244,7 @@ stringVector * FileDialog::doOpenMultiFilesDlg()
 		{
 			wcscpy_s(fn, _fileName);
 			if (fn[lstrlen(fn) - 1] != '\\')
-				lstrcat(fn, TEXT("\\"));
+				wcscat_s(fn, TEXT("\\"));
 		}
 
 		int term = lstrlen(fn);
@@ -252,7 +252,7 @@ stringVector * FileDialog::doOpenMultiFilesDlg()
 		while (*pFn)
 		{
 			fn[term] = '\0';
-			lstrcat(fn, pFn);
+			wcscat_s(fn, pFn);
 			_fileNames.push_back(generic_string(fn));
 			pFn += lstrlen(pFn) + 1;
 		}
diff --git a/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp b/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
index ea4a5a74..956ca558 100644
--- a/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
+++ b/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
@@ -336,7 +336,7 @@ INT_PTR CALLBACK WindowsDlg::run_dlgProc(UINT message, WPARAM wParam, LPARAM lPa
 							{
 								len += lstrlen(readonlyString);
 								if (len <= pLvdi->item.cchTextMax)
-									lstrcat(pLvdi->item.pszText, readonlyString);
+									wcscat_s(pLvdi->item.pszText, pLvdi->item.cchTextMax, readonlyString);
 							}
 						}
 						else if (pLvdi->item.iSubItem == 1) // directory
diff --git a/PowerEditor/src/winmain.cpp b/PowerEditor/src/winmain.cpp
index 470b09ec..65496927 100644
--- a/PowerEditor/src/winmain.cpp
+++ b/PowerEditor/src/winmain.cpp
@@ -542,7 +542,8 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR, int)
 		TCHAR str[50] = TEXT("God Damned Exception : ");
 		TCHAR code[10];
 		wsprintf(code, TEXT("%d"), i);
-		::MessageBox(Notepad_plus_Window::gNppHWND, lstrcat(str, code), TEXT("Int Exception"), MB_OK);
+		wcscat_s(str, code);
+		::MessageBox(Notepad_plus_Window::gNppHWND, str, TEXT("Int Exception"), MB_OK);
 		doException(notepad_plus_plus);
 	}
 	catch (std::runtime_error & ex)