diff --git a/src/spikeinterface/sorters/basesorter.py b/src/spikeinterface/sorters/basesorter.py
index 2f87065d9f..8c52626703 100644
--- a/src/spikeinterface/sorters/basesorter.py
+++ b/src/spikeinterface/sorters/basesorter.py
@@ -183,7 +183,7 @@ def set_params_to_folder(cls, recording, output_folder, new_params, verbose):
         # custom check params
         params = cls._check_params(recording, output_folder, params)
         # common check : filter warning
-        if recording.is_filtered and cls._check_apply_filter_in_params(params) and verbose:
+        if recording.is_filtered() and cls._check_apply_filter_in_params(params) and verbose:
             print(f"Warning! The recording is already filtered, but {cls.sorter_name} filter is enabled")
 
         # dump parameters inside the folder with json
diff --git a/src/spikeinterface/sorters/external/mountainsort5.py b/src/spikeinterface/sorters/external/mountainsort5.py
index 6fa68de190..cf6933c9e6 100644
--- a/src/spikeinterface/sorters/external/mountainsort5.py
+++ b/src/spikeinterface/sorters/external/mountainsort5.py
@@ -120,7 +120,6 @@ def _setup_recording(cls, recording, sorter_output_folder, params, verbose):
     @classmethod
     def _run_from_folder(cls, sorter_output_folder, params, verbose):
         import mountainsort5 as ms5
-        from mountainsort5.util import create_cached_recording
 
         recording = cls.load_recording_from_folder(sorter_output_folder.parent, with_warnings=False)
         if recording is None: