diff --git a/BizHawk.Client.DiscoHawk/DiscoHawk.cs b/BizHawk.Client.DiscoHawk/DiscoHawk.cs
index 884bc461a4..a68d8c2f53 100644
--- a/BizHawk.Client.DiscoHawk/DiscoHawk.cs
+++ b/BizHawk.Client.DiscoHawk/DiscoHawk.cs
@@ -4,6 +4,8 @@ using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Reflection;
 using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
 using System.IO;
 
 using BizHawk.Emulation.DiscSystem;
@@ -184,6 +186,33 @@ namespace BizHawk.Client.DiscoHawk
 
 	class DiscoHawk
 	{
+		static List<string> FindExtensionsRecurse(string dir, string extUppercaseWithDot)
+		{
+			List<string> ret = new List<string>();
+			Queue<string> dpTodo = new Queue<string>();
+			dpTodo.Enqueue(dir);
+			for (; ; )
+			{
+				string dpCurr;
+				if (dpTodo.Count == 0)
+					break;
+				dpCurr = dpTodo.Dequeue();
+				Parallel.ForEach(new DirectoryInfo(dpCurr).GetFiles(), (fi) =>
+				{
+					if (fi.Extension.ToUpperInvariant() == extUppercaseWithDot)
+						lock(ret)
+							ret.Add(fi.FullName);
+				});
+				Parallel.ForEach(new DirectoryInfo(dpCurr).GetDirectories(), (di) =>
+				{
+					lock(dpTodo)
+						dpTodo.Enqueue(di.FullName);
+				});
+			}
+
+			return ret;
+		}
+
 		public void Run(string[] args)
 		{
 			if (args.Length == 0)
@@ -193,6 +222,8 @@ namespace BizHawk.Client.DiscoHawk
 				return;
 			}
 
+			bool scanCues = false;
+			string dirArg = null;
 			string infile = null;
 			var loadDiscInterface = DiscInterface.BizHawk;
 			var compareDiscInterfaces = new List<DiscInterface> ();
@@ -209,192 +240,264 @@ namespace BizHawk.Client.DiscoHawk
 					compareDiscInterfaces.Add((DiscInterface)Enum.Parse(typeof(DiscInterface), args[idx++], true));
 				else if (au == "HAWK")
 					hawk = true;
+				else if (au == "CUEDIR")
+				{
+					dirArg = args[idx++];
+					scanCues = true;
+				}
 				else infile = a;
 			}
 
-			if (infile == null)
-				return;
-
-
 			if (hawk)
 			{
+				if (infile == null)
+					return;
+
 				//TODO - write it out
 				var dmj = new DiscMountJob { IN_DiscInterface = loadDiscInterface, IN_FromPath = infile };
 				dmj.Run();
 				//var disc = dmj.OUT_Disc;
 			}
 
-			StringWriter sw = new StringWriter();
-			foreach (var cmpif in compareDiscInterfaces)
+			bool verbose = true;
+
+			if (scanCues)
 			{
-				sw.WriteLine("BEGIN COMPARE: SRC {0} vs DST {1}", loadDiscInterface, cmpif);
-
-				//reload the original disc, with new policies as needed
-				var dmj = new DiscMountJob { IN_DiscInterface = loadDiscInterface, IN_FromPath = infile };
-				if (cmpif == DiscInterface.MednaDisc)
+				verbose = false;
+				var todo = FindExtensionsRecurse(dirArg, ".CUE");
+				var po = new ParallelOptions();
+				var cts = new CancellationTokenSource();
+				po.CancellationToken = cts.Token;
+				po.MaxDegreeOfParallelism = 1;
+				//po.MaxDegreeOfParallelism = System.Environment.ProcessorCount - 2; //I'm disk bound, no sense hammering this
+				if(po.MaxDegreeOfParallelism < 0) po.MaxDegreeOfParallelism = 1;
+				object olock = new object();
+				int ctr=0;
+				try
 				{
-					dmj.IN_DiscMountPolicy.CUE_PregapContradictionModeA = false;
-				}
-				dmj.Run();
-				var disc = dmj.OUT_Disc;
-
-				var src_disc = disc;
-
-				var dst_dmj = new DiscMountJob { IN_DiscInterface = cmpif, IN_FromPath = infile };
-				dst_dmj.Run();
-				var dst_disc = dst_dmj.OUT_Disc;
-
-				var src_dsr = new DiscSectorReader(src_disc);
-				var dst_dsr = new DiscSectorReader(dst_disc);
-
-				var src_toc = src_disc.TOCRaw;
-				var dst_toc = dst_disc.TOCRaw;
-
-				var src_databuf = new byte[2448];
-				var dst_databuf = new byte[2448];
-
-				Action<DiscTOCRaw.TOCItem> sw_dump_toc_one = (item) =>
+					Parallel.ForEach(todo, po, (fp) =>
 					{
-						if(!item.Exists)
-							sw.Write("(---missing---)");
-						else
-							sw.Write("({0:X2} - {1})",(byte)item.Control,item.LBATimestamp);
-					};
+						lock (olock)
+						{
+							ctr++;
+							int strlen = todo.Count.ToString().Length;
+							string fmt = string.Format("{{0,{0}}}/{{1,{0}}} {{2}}", strlen);
+							Console.WriteLine(fmt, ctr, todo.Count, Path.GetFileNameWithoutExtension(fp));
+						}
 
-				Action<int> sw_dump_toc = (index) =>
-				  {
-						sw.Write("SRC TOC#{0,3} ",index); sw_dump_toc_one(src_toc.TOCItems[index]); sw.WriteLine();
-						sw.Write("DST TOC#{0,3} ",index); sw_dump_toc_one(dst_toc.TOCItems[index]); sw.WriteLine();
-				  };
+						foreach (var cmpif in compareDiscInterfaces)
+						{
+							StringWriter sw = new StringWriter();
+							bool success = CompareFile(fp, loadDiscInterface, cmpif, verbose, cts, sw);
+							if (!success)
+							{
+								lock (Console.Out)
+									Console.Out.Write(sw.ToString());
 
-				//verify sector count
-				if (src_disc.LBACount != dst_disc.LBACount)
-				{
-					sw.Write("LBACount count {0} vs {1}\n", src_disc.LBACount, dst_disc.LBACount);
-					goto SKIPPO;
+								cts.Cancel();
+								return;
+							}
+						}
+					});
 				}
-
-				//verify TOC match
-				if (src_disc.TOCRaw.FirstRecordedTrackNumber != dst_disc.TOCRaw.FirstRecordedTrackNumber
-					|| src_disc.TOCRaw.LastRecordedTrackNumber != dst_disc.TOCRaw.LastRecordedTrackNumber)
-				{
-					sw.WriteLine("Mismatch of RecordedTrackNumbers: {0}-{1} vs {2}-{3}",
-						src_disc.TOCRaw.FirstRecordedTrackNumber, src_disc.TOCRaw.LastRecordedTrackNumber,
-						dst_disc.TOCRaw.FirstRecordedTrackNumber, dst_disc.TOCRaw.LastRecordedTrackNumber
-						);
-					goto SKIPPO;
+				catch (AggregateException ae) {
+					Console.WriteLine(ae.ToString());
 				}
+				Console.WriteLine("--TERMINATED--");
+				return;
+			}
 
-				bool badToc = false;
-				for (int t = 0; t < 101; t++)
+			if (compareDiscInterfaces.Count != 0)
+			{
+				StringWriter sw = new StringWriter();
+				foreach (var cmpif in compareDiscInterfaces)
+					CompareFile(infile, loadDiscInterface, cmpif, verbose, null, sw);
+				sw.Flush();
+				string results = sw.ToString();
+				var cr = new ComparisonResults();
+				cr.textBox1.Text = results;
+				cr.ShowDialog();
+			}
+
+
+		} //Run()
+
+		static bool CompareFile(string infile, DiscInterface loadDiscInterface, DiscInterface cmpif, bool verbose, CancellationTokenSource cancelToken, StringWriter sw)
+		{
+			bool success = false;
+
+			sw.WriteLine("BEGIN COMPARE: {0}\nSRC {1} vs DST {2}", infile, loadDiscInterface, cmpif);
+
+			//reload the original disc, with new policies as needed
+			var dmj = new DiscMountJob { IN_DiscInterface = loadDiscInterface, IN_FromPath = infile };
+			if (cmpif == DiscInterface.MednaDisc)
+			{
+				dmj.IN_DiscMountPolicy.CUE_PregapContradictionModeA = false;
+			}
+			dmj.Run();
+			var disc = dmj.OUT_Disc;
+
+			var src_disc = disc;
+
+			var dst_dmj = new DiscMountJob { IN_DiscInterface = cmpif, IN_FromPath = infile };
+			dst_dmj.Run();
+			var dst_disc = dst_dmj.OUT_Disc;
+
+			var src_dsr = new DiscSectorReader(src_disc);
+			var dst_dsr = new DiscSectorReader(dst_disc);
+
+			var src_toc = src_disc.TOCRaw;
+			var dst_toc = dst_disc.TOCRaw;
+
+			var src_databuf = new byte[2448];
+			var dst_databuf = new byte[2448];
+
+			Action<DiscTOCRaw.TOCItem> sw_dump_toc_one = (item) =>
+			{
+				if (!item.Exists)
+					sw.Write("(---missing---)");
+				else
+					sw.Write("({0:X2} - {1})", (byte)item.Control, item.LBATimestamp);
+			};
+
+
+			Action<int> sw_dump_toc = (index) =>
+			{
+				sw.Write("SRC TOC#{0,3} ", index); sw_dump_toc_one(src_toc.TOCItems[index]); sw.WriteLine();
+				sw.Write("DST TOC#{0,3} ", index); sw_dump_toc_one(dst_toc.TOCItems[index]); sw.WriteLine();
+			};
+
+			//verify sector count
+			if (src_disc.LBACount != dst_disc.LBACount)
+			{
+				sw.Write("LBACount count {0} vs {1}\n", src_disc.LBACount, dst_disc.LBACount);
+				goto SKIPPO;
+			}
+
+			//verify TOC match
+			if (src_disc.TOCRaw.FirstRecordedTrackNumber != dst_disc.TOCRaw.FirstRecordedTrackNumber
+				|| src_disc.TOCRaw.LastRecordedTrackNumber != dst_disc.TOCRaw.LastRecordedTrackNumber)
+			{
+				sw.WriteLine("Mismatch of RecordedTrackNumbers: {0}-{1} vs {2}-{3}",
+					src_disc.TOCRaw.FirstRecordedTrackNumber, src_disc.TOCRaw.LastRecordedTrackNumber,
+					dst_disc.TOCRaw.FirstRecordedTrackNumber, dst_disc.TOCRaw.LastRecordedTrackNumber
+					);
+				goto SKIPPO;
+			}
+
+			bool badToc = false;
+			for (int t = 0; t < 101; t++)
+			{
+				if (src_toc.TOCItems[t].Exists != dst_toc.TOCItems[t].Exists
+					|| src_toc.TOCItems[t].Control != dst_toc.TOCItems[t].Control
+					|| src_toc.TOCItems[t].LBATimestamp.Sector != dst_toc.TOCItems[t].LBATimestamp.Sector
+					)
 				{
-					if (src_toc.TOCItems[t].Exists != dst_toc.TOCItems[t].Exists
-						|| src_toc.TOCItems[t].Control != dst_toc.TOCItems[t].Control
-						|| src_toc.TOCItems[t].LBATimestamp.Sector != dst_toc.TOCItems[t].LBATimestamp.Sector
-						)
-					{
-						sw.WriteLine("Mismatch in TOCItem");
-						sw_dump_toc(t);
-						badToc = true;
-					}
+					sw.WriteLine("Mismatch in TOCItem");
+					sw_dump_toc(t);
+					badToc = true;
 				}
-				if(badToc)
-					goto SKIPPO;
+			}
+			if (badToc)
+				goto SKIPPO;
 
-				Action<string, int, byte[], int, int> sw_dump_chunk_one = (comment, lba, buf, addr, count) =>
+			Action<string, int, byte[], int, int> sw_dump_chunk_one = (comment, lba, buf, addr, count) =>
+			{
+				sw.Write("{0} -  ", comment);
+				for (int i = 0; i < count; i++)
 				{
-					sw.Write("{0} -  ", comment);
-					for (int i = 0; i < count; i++)
-					{
-						if (i + addr >= buf.Length) continue;
-						sw.Write("{0:X2}{1}", buf[addr + i], (i == count - 1) ? " " : "  ");
-					}
-					sw.WriteLine();
-				};
+					if (i + addr >= buf.Length) continue;
+					sw.Write("{0:X2}{1}", buf[addr + i], (i == count - 1) ? " " : "  ");
+				}
+				sw.WriteLine();
+			};
 
-				int[] offenders = new int[12];
-				Action<int, int, int, int, int> sw_dump_chunk = (lba, dispaddr, addr, count, numoffenders) =>
-				{
-					var hashedOffenders = new HashSet<int>();
-					for (int i = 0; i < numoffenders; i++) hashedOffenders.Add(offenders[i]);
-					sw.Write("                          ");
-					for (int i = 0; i < count; i++) sw.Write((hashedOffenders.Contains(dispaddr + i)) ? "vvv " : "    ");
-					sw.WriteLine();
-					sw.Write("                          ");
-					for (int i = 0; i < count; i++) sw.Write("{0:X3} ", dispaddr + i, (i == count - 1) ? " " : "  ");
-					sw.WriteLine();
-					sw.Write("                          ");
-					sw.Write(new string('-', count * 4));
-					sw.WriteLine();
-					sw_dump_chunk_one(string.Format("SRC #{0,6} ({1})", lba, new Timestamp(lba)), lba, src_databuf, addr, count);
-					sw_dump_chunk_one(string.Format("DST #{0,6} ({1})", lba, new Timestamp(lba)), lba, dst_databuf, addr, count);
-				};
+			int[] offenders = new int[12];
+			Action<int, int, int, int, int> sw_dump_chunk = (lba, dispaddr, addr, count, numoffenders) =>
+			{
+				var hashedOffenders = new HashSet<int>();
+				for (int i = 0; i < numoffenders; i++) hashedOffenders.Add(offenders[i]);
+				sw.Write("                          ");
+				for (int i = 0; i < count; i++) sw.Write((hashedOffenders.Contains(dispaddr + i)) ? "vvv " : "    ");
+				sw.WriteLine();
+				sw.Write("                          ");
+				for (int i = 0; i < count; i++) sw.Write("{0:X3} ", dispaddr + i, (i == count - 1) ? " " : "  ");
+				sw.WriteLine();
+				sw.Write("                          ");
+				sw.Write(new string('-', count * 4));
+				sw.WriteLine();
+				sw_dump_chunk_one(string.Format("SRC #{0,6} ({1})", lba, new Timestamp(lba)), lba, src_databuf, addr, count);
+				sw_dump_chunk_one(string.Format("DST #{0,6} ({1})", lba, new Timestamp(lba)), lba, dst_databuf, addr, count);
+			};
 
-				//verify each sector contents
-				int nSectors = src_disc.LBACount;
-				for (int lba = -150; lba < nSectors; lba++)
-				{
+			//verify each sector contents
+			int nSectors = src_disc.LBACount;
+			for (int lba = -150; lba < nSectors; lba++)
+			{
+				if(verbose)
 					if (lba % 1000 == 0)
 						Console.WriteLine("LBA {0} of {1}", lba, src_disc.LBACount);
 
-					src_dsr.ReadLBA_2442(lba, src_databuf, 0);
-					dst_dsr.ReadLBA_2442(lba, dst_databuf, 0);
+				if(cancelToken != null)
+					if (cancelToken.Token.IsCancellationRequested)
+						return false;
 
-					//check the header
-					for (int b = 0; b < 16; b++)
+				src_dsr.ReadLBA_2442(lba, src_databuf, 0);
+				dst_dsr.ReadLBA_2442(lba, dst_databuf, 0);
+
+				//check the header
+				for (int b = 0; b < 16; b++)
+				{
+					if (src_databuf[b] != dst_databuf[b])
 					{
-						if (src_databuf[b] != dst_databuf[b])
-						{
-							sw.WriteLine("Mismatch in sector header at byte {0}",b);
-							offenders[0] = b;
-							sw_dump_chunk(lba, 0, 0, 16, 1);
-							goto SKIPPO;
-						}
+						sw.WriteLine("Mismatch in sector header at byte {0}", b);
+						offenders[0] = b;
+						sw_dump_chunk(lba, 0, 0, 16, 1);
+						goto SKIPPO;
 					}
-
-					//check userdata
-					for (int b = 16; b < 2352; b++)
-					{
-						if (src_databuf[b] != dst_databuf[b])
-						{
-							sw.Write("LBA {0} mismatch at userdata byte {1}; terminating sector cmp\n", lba, b);
-							goto SKIPPO;
-						}
-					}
-
-					//check subchannels
-					for (int c = 0, b=2352; c < 8; c++)
-					{
-						int numOffenders = 0;
-						for (int e = 0; e < 12; e++, b++)
-						{
-							if (src_databuf[b] != dst_databuf[b])
-							{
-								offenders[numOffenders++] = e;
-							}
-						}
-						if (numOffenders != 0)
-						{
-							sw.Write("LBA {0} mismatch(es) at subchannel {1}; terminating sector cmp\n", lba, (char)('P' + c));
-							sw_dump_chunk(lba, 0, 2352 + c * 12, 12, numOffenders);
-							goto SKIPPO;
-						}
-					}
-
 				}
 
-			SKIPPO:
-				sw.WriteLine("END COMPARE");
-				sw.WriteLine("-----------------------------");
+				//check userdata
+				for (int b = 16; b < 2352; b++)
+				{
+					if (src_databuf[b] != dst_databuf[b])
+					{
+						sw.Write("LBA {0} mismatch at userdata byte {1}; terminating sector cmp\n", lba, b);
+						goto SKIPPO;
+					}
+				}
+
+				//check subchannels
+				for (int c = 0, b = 2352; c < 8; c++)
+				{
+					int numOffenders = 0;
+					for (int e = 0; e < 12; e++, b++)
+					{
+						if (src_databuf[b] != dst_databuf[b])
+						{
+							offenders[numOffenders++] = e;
+						}
+					}
+					if (numOffenders != 0)
+					{
+						sw.Write("LBA {0} mismatch(es) at subchannel {1}; terminating sector cmp\n", lba, (char)('P' + c));
+						sw_dump_chunk(lba, 0, 2352 + c * 12, 12, numOffenders);
+						goto SKIPPO;
+					}
+				}
 			}
 
-			sw.Flush();
-			var cr = new ComparisonResults();
-			string results = sw.ToString();
-			cr.textBox1.Text = results;
-			cr.ShowDialog();
-		}
-	}
+			success = true;
+
+		SKIPPO:
+			sw.WriteLine("END COMPARE");
+			sw.WriteLine("-----------------------------");
+
+			return success;
+		
+		} //CompareFile
+
+	} //class DiscoHawk
 
 }