diff --git a/src/PdfSharp/Pdf.IO/Parser.cs b/src/PdfSharp/Pdf.IO/Parser.cs
index a5d12ac3..c08e0af6 100644
--- a/src/PdfSharp/Pdf.IO/Parser.cs
+++ b/src/PdfSharp/Pdf.IO/Parser.cs
@@ -1031,30 +1031,142 @@ internal PdfTrailer ReadTrailer()
                 throw new Exception("The StartXRef table could not be found, the file cannot be opened.");
 
             ReadSymbol(Symbol.StartXRef);
-            _lexer.Position = ReadInteger();
+			int startxref = _lexer.Position = ReadInteger();
+
+			// Must be before the first 'goto valid_xref;' statement.
+			int xref_offset = 0;
+
+			// Check for valid startxref
+			if (IsValidXref())
+			{
+				goto valid_xref;
+			}
+
+			// If we reach this point, we have an invalid startxref
+			// First look for bytes preceding "%PDF-". Some pdf producers ignore these.
+			if (length >= 1024)
+			{
+				// "%PDF-" should be in this range
+				string header = _lexer.ReadRawString(0, 1024);
+				idx = header.IndexOf("%PDF-", StringComparison.Ordinal);
+			}
+			else
+			{
+				string header = _lexer.ReadRawString(0, length);
+				idx = header.IndexOf("%PDF-", StringComparison.Ordinal);
+			}
+
+			if (idx > 0)
+			{
+				//_lexer.ByteOffset = idx;
+				_lexer.Position = startxref + idx;
+				if (IsValidXref())
+				{
+					xref_offset = idx;
+					goto valid_xref;
+				}
+			}
+
+			valid_xref:
+			_lexer.Position = startxref + xref_offset;
+
+			// Read all trailers.
+			while (true)
+			{
+				PdfTrailer trailer = ReadXRefTableAndTrailer(_document._irefTable, xref_offset);
+				// 1st trailer seems to be the best.
+				if (_document._trailer == null)
+					_document._trailer = trailer;
+				int prev = trailer.Elements.GetInteger(PdfTrailer.Keys.Prev);
+				if (prev == 0)
+					break;
+				//if (prev > lexer.PdfLength)
+				//  break;
+				_lexer.Position = prev;
+			}
+
+			return _document._trailer;
+		}
 
-            // Read all trailers.
+        /// <summary>
+        /// Checks that the current _lexer location is a valid xref.
+        /// </summary>
+        /// <returns></returns>
+        private bool IsValidXref()
+        {
+            int length = _lexer.PdfLength;
+            int position = _lexer.Position;
+            // Make sure not inside a stream.
+
+            string content = "";
+            int content_pos = position;
             while (true)
             {
-                PdfTrailer trailer = ReadXRefTableAndTrailer(_document._irefTable);
-                // 1st trailer seems to be the best.
-                if (_document._trailer == null)
-                    _document._trailer = trailer;
-                int prev = trailer.Elements.GetInteger(PdfTrailer.Keys.Prev);
-                if (prev == 0)
+                // look for stream and endstream in 1k chunks.
+                int read_length = Math.Min(1024, length - content_pos);
+                content += _lexer.ReadRawString(content_pos, read_length);
+
+                int ss = content.IndexOf("stream", StringComparison.Ordinal);
+                int es = content.IndexOf("endstream", StringComparison.Ordinal);
+                int eof = content.IndexOf("%%EOF", StringComparison.Ordinal);
+
+                if (ss != es)
+                {
+                    if (ss == -1)
+                    {
+                        if (eof != -1 && eof < es)
+                            break;
+                        else
+                            return false;
+                    }
+                    else if (es == -1)
+                        break;
+                    else if (ss < es)
+                        break;
+                    else if (ss > es)
+                    {
+                        if (eof != -1 && eof < ss && eof < es)
+                            break;
+                        else
+                            return false;
+                    }
+                }
+
+                if (eof != -1)
                     break;
-                //if (prev > lexer.PdfLength)
-                //  break;
-                _lexer.Position = prev;
+
+                content_pos = content_pos + read_length;
+                if (content_pos + read_length >= length)
+                {
+                    // reached the end of the document without finding either.
+                    break;
+                }
             }
 
-            return _document._trailer;
+            _lexer.Position = position;
+
+            Symbol symbol = ScanNextToken();
+            if (symbol == Symbol.XRef)
+            {
+                return true;
+            }
+
+            if (symbol == Symbol.Integer)
+            {
+                // Just because we have an integer, doesn't mean the startxref is actually valid
+                if (ScanNextToken() == Symbol.Integer && ScanNextToken() == Symbol.Obj)
+                {
+                    return true;
+                }
+            }
+
+            return false;
         }
 
         /// <summary>
         /// Reads cross reference table(s) and trailer(s).
         /// </summary>
-        private PdfTrailer ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable)
+        private PdfTrailer ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable, int xrefOffset)
         {
             Debug.Assert(xrefTable != null);
 
@@ -1072,7 +1184,7 @@ private PdfTrailer ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable)
                         int length = ReadInteger();
                         for (int id = start; id < start + length; id++)
                         {
-                            int position = ReadInteger();
+                            int position = ReadInteger() + xrefOffset;
                             int generation = ReadInteger();
                             ReadSymbol(Symbol.Keyword);
                             string token = _lexer.Token;
@@ -1114,10 +1226,10 @@ private PdfTrailer ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable)
             return null;
         }
 
-        /// <summary>
-        /// Reads cross reference stream(s).
-        /// </summary>
-        private PdfTrailer ReadXRefStream(PdfCrossReferenceTable xrefTable)
+		/// <summary>
+		/// Reads cross reference stream(s).
+		/// </summary>
+		private PdfTrailer ReadXRefStream(PdfCrossReferenceTable xrefTable)
         {
             // Read cross reference stream.
             //Debug.Assert(_lexer.Symbol == Symbol.Integer);