diff -r fab0b8a61dcb -r 45e2bb06c88d librazor/merger.c
--- a/librazor/merger.c	Wed Aug 20 18:57:52 2014 +0100
+++ b/librazor/merger.c	Fri Apr 15 16:57:55 2016 +0100
@@ -318,8 +318,14 @@
 	set2 = merger->source2.set;
 	map1 = merger->source1.file_map;
 	map2 = merger->source2.file_map;
-	pool1 = set1->file_string_pool.data;
-	pool2 = set2->file_string_pool.data;
+	if (set1->file_string_pool.size)
+		pool1 = set1->file_string_pool.data;
+	else
+		pool1 = NULL;
+	if (set2->file_string_pool.size)
+		pool2 = set2->file_string_pool.data;
+	else
+		pool2 = NULL;
 	root1 = (struct razor_entry *) set1->files.data;
 	root2 = (struct razor_entry *) set2->files.data;
 
@@ -349,9 +355,9 @@
 			continue;
 		}
 
-		if (!e1)
+		if (!e1 || !pool1)
 			cmp = 1;
-		else if (!e2)
+		else if (!e2 || !pool2)
 			cmp = -1;
 		else {
 			cmp = strcmp (&pool1[e1->name],
@@ -631,5 +637,9 @@
 	hashtable_release(&merger->table);
 	hashtable_release(&merger->file_table);
 	hashtable_release(&merger->details_table);
+	free(merger->source1.property_map);
+	free(merger->source1.file_map);
+	free(merger->source2.property_map);
+	free(merger->source2.file_map);
 	free(merger);
 }