diff --git a/doc/Realsense.md b/doc/Realsense.md
index b75ce3d..71038d9 100644
--- a/doc/Realsense.md
+++ b/doc/Realsense.md
@@ -141,6 +141,8 @@ You should be able to see that, despite some noise, rotational velocity computed
 You can also switch to the error function plot and see that there is a clear minimum corresponding to the computed time offset.
 ![t265_time_align_error](/doc/img/t265_time_align_error.png)
 
+**Note:** If you want to run the time alignment again you should delete the `~/t265_calib_data/sequence0/mav/gt` folder first.
+
 ## Running Visual-Inertial Odometry
 Now we can run the visual-inertial odometry on the recorded dataset:
 ```