diff --git a/src/dsp_tools/excel2xml.py b/src/dsp_tools/excel2xml.py
index 458e93a7f..92c777809 100644
--- a/src/dsp_tools/excel2xml.py
+++ b/src/dsp_tools/excel2xml.py
@@ -1902,8 +1902,8 @@ def _validate_and_prepare_cli_input_file(dataframe: pd.DataFrame) -> pd.DataFram
     )
 
     # remove empty columns/rows
-    dataframe.dropna(axis="columns", how="all", inplace=True)
-    dataframe.dropna(axis="index", how="all", inplace=True)
+    dataframe = dataframe.dropna(axis="columns", how="all")
+    dataframe = dataframe.dropna(axis="index", how="all")
 
     return dataframe
 
diff --git a/src/dsp_tools/utils/excel2json/properties.py b/src/dsp_tools/utils/excel2json/properties.py
index a865c0670..95b37dfb8 100644
--- a/src/dsp_tools/utils/excel2json/properties.py
+++ b/src/dsp_tools/utils/excel2json/properties.py
@@ -362,7 +362,7 @@ def _rename_deprecated_hlist(df: pd.DataFrame, excelfile: str) -> pd.DataFrame:
         # In case there is a hlist, it is the only valid value in gui_attributes and has precedence
         df["hlist"] = df["hlist"].fillna(df["gui_attributes"])
         df.pop("gui_attributes")
-    df.rename(columns={"hlist": "gui_attributes"}, inplace=True)
+    df = df.rename(columns={"hlist": "gui_attributes"})
     return df
 
 
@@ -392,7 +392,7 @@ def _rename_deprecated_lang_cols(df: pd.DataFrame, excelfile: str) -> pd.DataFra
             f"Please use {[f'label_{lang}' for lang in languages]}"
         )
     rename_dict = dict(zip(languages, language_label_col))
-    df.rename(columns=rename_dict, inplace=True)
+    df = df.rename(columns=rename_dict)
     return df
 
 
diff --git a/src/dsp_tools/utils/excel2json/utils.py b/src/dsp_tools/utils/excel2json/utils.py
index 4765d7186..ef93a2930 100644
--- a/src/dsp_tools/utils/excel2json/utils.py
+++ b/src/dsp_tools/utils/excel2json/utils.py
@@ -60,7 +60,7 @@ def clean_data_frame(df: pd.DataFrame) -> pd.DataFrame:
         lambda x: str(x).strip() if pd.notna(x) and regex.search(r"[\w\p{L}]", str(x), flags=regex.U) else pd.NA
     )
     # drop all the rows that are entirely empty
-    df.dropna(axis=0, how="all", inplace=True)
+    df = df.dropna(axis=0, how="all")
     return df
 
 
diff --git a/test/unittests/test_excel2json/test_lists.py b/test/unittests/test_excel2json/test_lists.py
index e149a9af9..8eea6bd1f 100644
--- a/test/unittests/test_excel2json/test_lists.py
+++ b/test/unittests/test_excel2json/test_lists.py
@@ -93,7 +93,7 @@ def test_excel2lists(self) -> None:
             input_df = input_df.map(
                 lambda x: x if pd.notna(x) and regex.search(r"\p{L}", str(x), flags=regex.UNICODE) else pd.NA
             )
-            input_df.dropna(axis="index", how="all", inplace=True)
+            input_df = input_df.dropna(axis="index", how="all")
             excelfolder = f"testdata/excel2json/lists-{mode}"
             outfile = f"testdata/tmp/lists_output_{mode}.json"
             output_from_method, _ = e2l.excel2lists(excelfolder=excelfolder, path_to_output_file=outfile)
diff --git a/test/unittests/test_excel2json/test_properties.py b/test/unittests/test_excel2json/test_properties.py
index 320ea0bfa..553cc17c7 100644
--- a/test/unittests/test_excel2json/test_properties.py
+++ b/test/unittests/test_excel2json/test_properties.py
@@ -370,9 +370,9 @@ def test__rename_deprecated_lang_cols(self) -> None:
             }
         )
         returned_df = e2j._rename_deprecated_lang_cols(df=original_df, excelfile="Test")
-        assert_frame_equal(original_df, returned_df)
+        assert_frame_equal(expected_df, returned_df)
         returned_df = e2j._rename_deprecated_lang_cols(df=expected_df, excelfile="Test")
-        assert_frame_equal(original_df, returned_df)
+        assert_frame_equal(expected_df, returned_df)
 
     def test__do_property_excel_compliance(self) -> None:
         original_df = pd.DataFrame(