--- a/tag.c
+++ b/tag.c
@@ -714,9 +714,12 @@
 
   frame = id3_tag_findframe(tag, ID3_FRAME_TRACK, 0);
   if (frame) {
-    unsigned int track;
+    id3_ucs4_t const *string;
+    unsigned int track = 0;
 
-    track = id3_ucs4_getnumber(id3_field_getstrings(&frame->fields[1], 0));
+	string = id3_field_getstrings(&frame->fields[1], 0);
+	if (string)
+    	track = id3_ucs4_getnumber(string);
     if (track > 0 && track <= 0xff) {
       ptr[-2] = 0;
       ptr[-1] = track;