diff --git a/Staging/VBoxHfs/fsw_hfs.c b/Staging/VBoxHfs/fsw_hfs.c
index a5b3565d..9ca3d0f1 100644
--- a/Staging/VBoxHfs/fsw_hfs.c
+++ b/Staging/VBoxHfs/fsw_hfs.c
@@ -1042,20 +1042,20 @@ fsw_hfs_cmpf_catkey (BTreeKey *btkey1, BTreeKey *btkey2)

 		for (ac = 0; ac == 0 && apos < ckey1nlen; apos++) {
 			ac = be16_to_cpu (p1[apos]);
-			ac = fsw_to_lower (ac);
+			ac = ac ? fsw_to_lower (ac) : 0xFFFF;
 		}

 		/* get next valid character from ckey2 */

 		for (bc = 0; bc == 0 && bpos < ckey2nlen; bpos++) {
 			bc = p2[bpos];
-			bc = fsw_to_lower (bc);
+			bc = bc ? fsw_to_lower (bc) : 0xFFFF;
 		}

 		if (ac != bc)
 			break;

-		if (ac == 0)
+		if (bpos == ckey1nlen)
 			return 0;
 	}