diff --git a/inst/NEWS.Rd b/inst/NEWS.Rd
index b2c881d..1bf1bb4 100644
--- a/inst/NEWS.Rd
+++ b/inst/NEWS.Rd
@@ -3,6 +3,13 @@
 
 \newcommand{\ghit}{\href{https://github.com/fgcz/rawrr/issues/#1}{##1}}
 
+\section{Changes in version 1.11 (2023-11-01)}{
+  \itemize{
+	  \item Fix index error \ghit{67}. 
+  }
+}
+
+
 \section{Changes in version 1.9.2 (2023-10-24)}{
   \itemize{
 	  \item Download RawFileReader DLL’s from  \url{https://github.com/thermofisherlsms/RawFileReader} \ghit{66}. 
diff --git a/inst/rawrrassembly/rawrr.cs b/inst/rawrrassembly/rawrr.cs
index f6cbfb8..945414a 100644
--- a/inst/rawrrassembly/rawrr.cs
+++ b/inst/rawrrassembly/rawrr.cs
@@ -373,7 +373,7 @@ public static void WriteTrailerValues(this IRawDataPlus rawFile, string label)
                         return;
 		    }
 
-		    for  (int scanNumber = rawFile.RunHeaderEx.FirstSpectrum; scanNumber < rawFile.RunHeaderEx.LastSpectrum; scanNumber++)
+		    foreach (int scanNumber in Enumerable.Range(rawFile.RunHeaderEx.FirstSpectrum, rawFile.RunHeaderEx.LastSpectrum))
                     {
                         var scanTrailer = rawFile.GetTrailerExtraInformation(scanNumber);
                     	Console.WriteLine(scanTrailer.Values.ToArray()[idx]);
diff --git a/tests/testthat/test-index.R b/tests/testthat/test-index.R
index 04da4f3..0024806 100644
--- a/tests/testthat/test-index.R
+++ b/tests/testthat/test-index.R
@@ -9,7 +9,7 @@ test_that("check readIndex.", {
     rawrr::readIndex() |>
     rawrr::validate_rawrrIndex()
 
-  expect_equivalent(dim(x) == c(573, 9),
+  expect_equivalent(dim(x) == c(574, 9),
       c(TRUE, TRUE))
   expect_true(is.data.frame(x))
   IndexColNames <- c("scan", "scanType", "StartTime", "precursorMass",