diff --git a/include/xlnt/worksheet/range.hpp b/include/xlnt/worksheet/range.hpp
index 58e1953f..38dcca84 100644
--- a/include/xlnt/worksheet/range.hpp
+++ b/include/xlnt/worksheet/range.hpp
@@ -173,7 +173,7 @@ public:
 	/// <summary>
 	/// 
 	/// </summary>
-	conditional_format conditional_format(const condition &when);
+	xlnt::conditional_format conditional_format(const condition &when);
 
     /// <summary>
     /// Returns the first row or column in this range.
diff --git a/include/xlnt/worksheet/worksheet.hpp b/include/xlnt/worksheet/worksheet.hpp
index 77ad3c1e..764afd1a 100644
--- a/include/xlnt/worksheet/worksheet.hpp
+++ b/include/xlnt/worksheet/worksheet.hpp
@@ -661,7 +661,7 @@ public:
 	/// <summary>
 	/// Creates a conditional format for the given range with the given condition.
 	/// </summary>
-	conditional_format conditional_format(const range_reference &ref, const condition &when);
+	xlnt::conditional_format conditional_format(const range_reference &ref, const condition &when);
 
 private:
     friend class cell;
diff --git a/source/detail/stylesheet.hpp b/source/detail/stylesheet.hpp
index 21d16226..c0261de6 100644
--- a/source/detail/stylesheet.hpp
+++ b/source/detail/stylesheet.hpp
@@ -66,6 +66,7 @@ struct stylesheet
     {
         auto iter = format_impls.begin();
         std::advance(iter, static_cast<std::list<format_impl>::difference_type>(index));
+
         return xlnt::format(&*iter);
     }
 
@@ -497,6 +498,7 @@ struct stylesheet
     
     void clear()
     {
+		conditional_format_impls.clear();
         format_impls.clear();
         
         style_impls.clear();
diff --git a/source/detail/xlsx_producer.cpp b/source/detail/xlsx_producer.cpp
index 77014129..99890170 100755
--- a/source/detail/xlsx_producer.cpp
+++ b/source/detail/xlsx_producer.cpp
@@ -2364,7 +2364,7 @@ void xlsx_producer::write_worksheet(const relationship &rel)
         write_end_element(xmlns, "mergeCells");
     }
 
-	// scope for conditional formatting production logic
+	if (source_.impl().stylesheet_.is_set())
 	{
 		const auto &stylesheet = source_.impl().stylesheet_.get();
 		const auto &cf_impls = stylesheet.conditional_format_impls;