diff --git a/source/Sylvan.Data.Csv/CsvDataReader+Async.cs b/source/Sylvan.Data.Csv/CsvDataReader+Async.cs
index 3b17c73..acea491 100644
--- a/source/Sylvan.Data.Csv/CsvDataReader+Async.cs
+++ b/source/Sylvan.Data.Csv/CsvDataReader+Async.cs
@@ -142,7 +142,8 @@ async Task<bool> InitializeReaderAsync(CancellationToken cancel = default)
 		}
 		if (this.newLineMode == NewLineMode.Unknown)
 		{
-			this.DetectNewLine();
+			var m = this.DetectNewLine();
+			this.newLineMode = m;
 		}
 
 		this.minSafe = delimiter < '\r' ? '\r' : delimiter;
diff --git a/source/Sylvan.Data.Csv/CsvDataReader.cs b/source/Sylvan.Data.Csv/CsvDataReader.cs
index e1b327f..fc849fc 100644
--- a/source/Sylvan.Data.Csv/CsvDataReader.cs
+++ b/source/Sylvan.Data.Csv/CsvDataReader.cs
@@ -294,7 +294,7 @@ NewLineMode DetectNewLine()
 		var c = this.buffer[idx];
 		if (c == '\r')
 		{
-			if (c + 1 < this.buffer.Length && this.buffer[c + 1] != '\n')
+			if (idx + 1 < this.buffer.Length && this.buffer[idx + 1] != '\n')
 			{
 				return NewLineMode.MacOS;
 			}