diff --git a/synergy/CClipboard.cpp b/synergy/CClipboard.cpp
index 8862d769..56a2d41a 100644
--- a/synergy/CClipboard.cpp
+++ b/synergy/CClipboard.cpp
@@ -146,9 +146,13 @@ CClipboard::unmarshall(const CString& data, Time time)
 		UInt32 size = readUInt32(index);
 		index += 4;
 
-		// save the data
-		m_added[format] = true;
-		m_data[format]  = CString(index, size);
+		// save the data if it's a known format.  if either the client
+		// or server supports more clipboard formats than the other
+		// then one of them will get a format >= kNumFormats here.
+		if (format < static_cast<UInt32>(IClipboard::kNumFormats)) {
+			m_added[format] = true;
+			m_data[format]  = CString(index, size);
+		}
 		index += size;
 	}
 
diff --git a/synergy/IClipboard.h b/synergy/IClipboard.h
index 2c145315..cd56d9e2 100644
--- a/synergy/IClipboard.h
+++ b/synergy/IClipboard.h
@@ -17,9 +17,9 @@ public:
 	// data set via add() and retrieved via get() is in one of
 	// these formats.  platform dependent clipboard subclasses
 	// can and should present any suitable formats derivable
-	// from these formats (e.g. UCS-16 encoded unicode).
+	// from these formats (e.g. UTF-16 encoded unicode).
 	//
-	// kText:  UTF-8 encoded unicode (ISO-10646), newline is LF
+	// kText:  UTF-8 encoded unicode (ISO-10646), newline is LF.
 	enum EFormat { kText, kNumFormats };
 
 	// manipulators