diff --git a/oemof_b3/tools/data_processing.py b/oemof_b3/tools/data_processing.py
index 44e6b5f8..aea85d26 100644
--- a/oemof_b3/tools/data_processing.py
+++ b/oemof_b3/tools/data_processing.py
@@ -1053,9 +1053,10 @@ def unstack_timeseries(df):
     lost_columns = ["source", "comment"]
     for col in lost_columns:
         if col in list(df.columns):
-            logger.warning(
-                f"Caution any remarks in column '{col}' are lost after unstacking."
-            )
+            if not _df[col].isna().all() or _df[col].values.all() == "None":
+                logger.warning(
+                    f"Caution any remarks in column '{col}' are lost after unstacking."
+                )
 
     # Process values of series
     values_series = []
diff --git a/tests/_files/oemof_b3_resources_timeseries_stacked_comments.csv b/tests/_files/oemof_b3_resources_timeseries_stacked_comments.csv
new file mode 100644
index 00000000..d3b523d8
--- /dev/null
+++ b/tests/_files/oemof_b3_resources_timeseries_stacked_comments.csv
@@ -0,0 +1,19 @@
+id_ts;region;var_name;timeindex_start;timeindex_stop;timeindex_resolution;series;var_unit;source;comment
+0;BB;biomass-st_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+1;BB;ch4-gt_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+2;BB;electricity-curtailment_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+3;BB;electricity-demand_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[1889794.8071409904, 1870448.7801216468, 1803840.2010708163];;;We have a comment here.
+4;BB;electricity-liion-battery_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+5;BB;electricity-liion-battery_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[882505.2, 1194379.0, 1289504.5];;;We have a comment here.
+6;BB;electricity-shortage_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+7;BB;solar-pv_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+8;BB;wind-onshore_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[1145114.0, 801141.1, 595497.8];;;We have a comment here.
+9;BE;biomass-st_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+10;BE;ch4-gt_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+11;BE;electricity-curtailment_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+12;BE;electricity-demand_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[1889794.8071409904, 1870448.7801216468, 1803840.2010708163];;;We have a comment here.
+13;BE;electricity-liion-battery_in_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+14;BE;electricity-liion-battery_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[882505.2, 1194379.0, 1289504.5];;;We have a comment here.
+15;BE;electricity-shortage_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+16;BE;solar-pv_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[0.0, 0.0, 0.0];;;We have a comment here.
+17;BE;wind-onshore_out_electricity;2019-01-01 00:00:00;2019-01-01 02:00:00;H;[1145114.0, 801141.1, 595497.8];;;We have a comment here.
diff --git a/tests/test_data_processing.py b/tests/test_data_processing.py
index 215eb371..64c9d4ad 100644
--- a/tests/test_data_processing.py
+++ b/tests/test_data_processing.py
@@ -2,6 +2,8 @@
 import numpy as np
 import pandas as pd
 import pytest
+import unittest
+from unittest.mock import patch
 
 from oemof_b3.tools.data_processing import (
     HEADER_B3_SCAL,
@@ -38,6 +40,9 @@ def full_path(filename):
 )
 path_file_sc_mixed_types = full_path("oemof_b3_resources_scalars_mixed_types.csv")
 path_file_ts_stacked = full_path("oemof_b3_resources_timeseries_stacked.csv")
+path_file_ts_stacked_comments = full_path(
+    "oemof_b3_resources_timeseries_stacked_comments.csv"
+)
 path_oemof_results_flows = full_path("oemof_results_flows.csv")
 path_oemof_b3_results_timeseries_flows = full_path(
     "oemof_b3_results_timeseries_flows.csv"
@@ -482,6 +487,57 @@ def test_unstack_stack_scalars_on_example_data():
     assert pd.testing.assert_frame_equal(df, df_stacked) is None
 
 
+class test_unstack_warning_source_comment(unittest.TestCase):
+    """
+    This test verifies whether the caution message is appropriately raised
+    when executing the function unstack_timeseries(). The caution message will
+    be raised if source and comments are not empty.
+    """
+
+    def setUp(self):
+        self.df_with_comments = load_b3_timeseries(path_file_ts_stacked_comments)
+        self.df_wo_comments = load_b3_timeseries(path_file_ts_stacked)
+
+    # Assert WARNING with unstack_timeseries(df_with_comments)
+    def test_unstack_warning_source_comment(self):
+        # Patch the logger.warning method to capture the warning calls
+        with patch(
+            "oemof_b3.tools.data_processing.logger.warning"
+        ) as mock_logger_warning:
+            # Call the function with df_with_comments, which should raise a warning
+            unstack_timeseries(self.df_with_comments)
+
+        # Check if the logger.warning was called with the expected messages
+        expected_warnings = [
+            "Caution any remarks in column 'source' are lost after unstacking.",
+            "Caution any remarks in column 'comment' are lost after unstacking.",
+        ]
+
+        # Check if any of the expected warning messages are contained
+        # in the captured warning messages
+        warnings_called = [call[0][0] for call in mock_logger_warning.call_args_list]
+
+        self.assertTrue(
+            any(warning_msg in warnings_called for warning_msg in expected_warnings)
+        )
+
+    # Assert that unstack_timeseries(df_wo_comments) does not give the warning:
+    def test_unstack_no_warning(self):
+        # Patch the logger.warning method to capture the warning calls
+        with patch(
+            "oemof_b3.tools.data_processing.logger.warning"
+        ) as mock_logger_warning:
+            # Call the function with df_wo_comments, which should not raise a warning
+            unstack_timeseries(self.df_wo_comments)
+
+        # Check that logger.warning was not called in this case
+        mock_logger_warning.assert_not_called()
+
+
+if __name__ == "__main__":
+    unittest.main()
+
+
 def test_merge_a_into_b():
     r"""
     Tests merge function.