diff --git a/src/openflexure_microscope_server/scan_directories.py b/src/openflexure_microscope_server/scan_directories.py
index 295c36dd..4f2e5215 100644
--- a/src/openflexure_microscope_server/scan_directories.py
+++ b/src/openflexure_microscope_server/scan_directories.py
@@ -353,6 +353,9 @@ class ScanDirectoryManager:
         For more explanation on the scan naming see `new_scan_dir`
         """
         scan_name = make_name_safe(scan_name)
+
+        # Strip all trailing underscores from the base name
+        scan_name = scan_name.strip("_")
         # A regex with the scan name and a group for the numbers
         scan_regex = re.compile(
             "^" + scan_name + "_([0-9]{" + str(SCAN_ZERO_PAD_DIGITS) + "})$"
diff --git a/tests/unit_tests/test_scan_directories.py b/tests/unit_tests/test_scan_directories.py
index 80121a32..0fc157fc 100644
--- a/tests/unit_tests/test_scan_directories.py
+++ b/tests/unit_tests/test_scan_directories.py
@@ -167,7 +167,7 @@ def test_bad_scan_names():
     scan_dir = scan_dir_manager.new_scan_dir("fake scan")
     assert scan_dir.name == "fake_scan_0001"
     scan_dir = scan_dir_manager.new_scan_dir("fake scan;rm -rf /;")
-    assert scan_dir.name == "fake_scan_rm_-rf____0001"
+    assert scan_dir.name == "fake_scan_rm_-rf_0001"
 
 
 def test_scan_sequence_and_listing(caplog):
@@ -277,6 +277,33 @@ def test_scan_sequence_case_sensitive():
     assert "fake_scan_0005" in all_scans
 
 
+def test_scan_names_have_single_underscores():
+    """Check created scans have only one underscore in them, not two."""
+    _clear_scan_dir()
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+
+    # Create some scan data and mark it as successful to get an end date.
+    scan_data = fake_active_scan_data()
+    scan_data.set_final_data(result="Success")
+    # Make 4 scans
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan_")
+    scan_dir.save_scan_data(scan_data)
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan__")
+    scan_dir.save_scan_data(scan_data)
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan_______")
+    scan_dir.save_scan_data(scan_data)
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+    scan_dir.save_scan_data(scan_data)
+
+    # Check they exist and are numbered sequentially
+    all_scans = scan_dir_manager.all_scans
+    assert_unique_of_length(all_scans, 4)
+    assert "fake_scan_0001" in all_scans
+    assert "fake_scan_0002" in all_scans
+    assert "fake_scan_0003" in all_scans
+    assert "fake_scan_0004" in all_scans
+
+
 def test_scan_name_non_sequential():
     """Check new scan has the correct name if the directories are not sequential."""
     _clear_scan_dir()