--- res/res_musiconhold.c	2007-02-01 16:11:28.000000000 -0500
+++ res/res_musiconhold.moo	2007-07-06 14:55:12.000000000 -0400
@@ -73,6 +73,7 @@
 #include "asterisk/linkedlists.h"
 
 #define INITIAL_NUM_FILES   8
+#define DEFAULT_CLASS "default"
 
 static char *app0 = "MusicOnHold";
 static char *app1 = "WaitMusicOnHold";
@@ -914,6 +915,31 @@
 	}
 }
 
+static struct mohclass *moh_getclass(const char *class)          
+{
+	struct mohclass *moh = NULL;     
+	
+	AST_LIST_LOCK(&mohclasses);              
+	moh = get_mohbyname(class);         
+	AST_LIST_UNLOCK(&mohclasses);
+	
+	return moh;
+}
+
+static int moh_classexist(const char *class)
+{
+	if (!ast_strlen_zero(class)) { 
+		if (!moh_getclass(class)) {
+			ast_log(LOG_WARNING, "No Class: %s\n", class);
+			return 0;
+		}
+		else
+			return 1;
+	}
+	else
+		return 0;
+}
+
 static int local_ast_moh_start(struct ast_channel *chan, const char *mclass, const char *interpclass)
 {
 	struct mohclass *mohclass;
@@ -930,24 +956,21 @@
 	 *    option.
 	 * 4) The default class.
 	 */
-	if (!ast_strlen_zero(chan->musicclass))
+	if (moh_classexist(chan->musicclass))
 		class = chan->musicclass;
-	else if (!ast_strlen_zero(mclass))
+	else if (moh_classexist(mclass))
 		class = mclass;
-	else if (!ast_strlen_zero(interpclass))
+        else if (moh_classexist(interpclass))
 		class = interpclass;
-	else
-		class = "default";
-
-	AST_LIST_LOCK(&mohclasses);
-	mohclass = get_mohbyname(class);
-	AST_LIST_UNLOCK(&mohclasses);
-
-	if (!mohclass) {
-		ast_log(LOG_WARNING, "No class: %s\n", class);
+        else if (moh_classexist(DEFAULT_CLASS))
+		class = DEFAULT_CLASS;
+	else {
+		ast_log(LOG_WARNING, "Could not find acceptable Music On Hold Class, ending Music On Hold");
 		return -1;
 	}
 
+	mohclass = moh_getclass(class);
+
 	ast_set_flag(chan, AST_FLAG_MOH);
 	if (mohclass->total_files) {
 		return ast_activate_generator(chan, &moh_file_stream, mohclass);