diff --git a/.gitignore b/.gitignore
index c15f7c10..33b8397e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -109,4 +109,5 @@ settings.json
 test_config/good_for_refl/refl/velocity.txt
 test_config/good_for_refl/refl/params.txt
 test_config/refl_init/refl/velocity.txt
-test_data/muontpar/test_write.tpar
+test_data/muontpar/current.tpar
+test_data/muontpar/current_booster.tpar
diff --git a/tests/muontpar.py b/tests/muontpar.py
index f4963037..1f81164f 100644
--- a/tests/muontpar.py
+++ b/tests/muontpar.py
@@ -1,5 +1,5 @@
-import os
 import unittest
+from pathlib import PureWindowsPath
 
 from utils.channel_access import ChannelAccess
 from utils.ioc_launcher import (
@@ -7,36 +7,28 @@
     get_default_ioc_dir,
 )
 from utils.test_modes import TestModes
-from utils.testing import ManagerMode
 
 ioc_number = 1
 DEVICE_PREFIX = "MUONTPAR_01"
 
-test_config_path = os.path.abspath(
-    os.path.join(os.path.dirname(os.path.dirname(__file__)), "test_data", "muontpar")
-).replace("\\", "/")
-
-
+test_config_path = PureWindowsPath(__file__).parent.parent / "test_data" / "muontpar"
+DEFAULT_INPUT_FILE = "tpar.tpar"
+DEFAULT_OUTPUT_FILE = "current.tpar"
 IOCS = [
-    {
-        # INSTETC is required to control manager mode.
-        "name": "INSTETC",
-        "directory": get_default_ioc_dir("INSTETC"),
-        "custom_prefix": "CS",
-        "pv_for_existence": "MANAGER",
-    },
     {
         "name": DEVICE_PREFIX,
         "directory": get_default_ioc_dir("MUONTPAR"),
         "pv_for_existence": "FILE_DIR",
-        "macros": {"EDITOR_TPAR_FILE_DIR": test_config_path},
+        "macros": {
+            "EDITOR_TPAR_FILE_DIR": str(test_config_path).replace("\\", "\\\\"),
+            "TPAR_FILE": DEFAULT_INPUT_FILE,
+        },
     },
 ]
 
 
 TEST_MODES = [TestModes.RECSIM]
-TEST_TPAR = """
-/   TLOW      THIGH    CYCLE    PROP    INT      DER     ACCUR     WAIT    TMOUT
+TEST_TPAR = """/   TLOW      THIGH    CYCLE    PROP    INT      DER     ACCUR     WAIT    TMOUT
 / --------   --------  ------  ------  ------  -------  --------   ----    -----
  0001.000   095.000   100.00  003.00  050.00  008.000  0000.400     5.      61. 
  0095.000   145.000   100.00  001.50  070.00  012.000  0000.400     5.      62. 
@@ -45,7 +37,6 @@
  0250.000   701.000   100.00  001.50  250.00  050.000  0002.000     10.      60.
 
 """
-TEST_TPAR_FILENAME = "test_write.tpar"
 
 
 class MuonTPARTests(unittest.TestCase):
@@ -56,49 +47,30 @@ class MuonTPARTests(unittest.TestCase):
     def setUp(self):
         self._ioc = IOCRegister.get_running(DEVICE_PREFIX)
         self.ca = ChannelAccess(5, device_prefix=DEVICE_PREFIX, default_wait_time=0.0)
-        if os.path.exists(os.path.join(test_config_path, TEST_TPAR_FILENAME)):
-            os.remove(os.path.join(test_config_path, TEST_TPAR_FILENAME))
 
     def test_tpar_dir_populates_file_dir_pv(self):
-        self.ca.assert_that_pv_is("FILE_DIR", test_config_path)
+        self.ca.assert_that_pv_is("FILE_DIR", str(test_config_path))
 
     def test_tpar_file_contents_match_disk_contents_on_read(self):
-        file_name = "tpar.tpar"
-        self.ca.set_pv_value("FILE_NAME:SP", file_name)
-        self.ca.assert_that_pv_is("FILE_NAME", file_name)
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "No")
-        with open(os.path.join(test_config_path, file_name), "r") as tpar_file:
+        self.ca.assert_that_pv_is("INPUT_FILE", DEFAULT_INPUT_FILE)
+        self.ca.assert_that_pv_is("OUTPUT_FILE", DEFAULT_OUTPUT_FILE)
+        with open(test_config_path / DEFAULT_OUTPUT_FILE, "r") as tpar_file:
             self.ca.assert_that_pv_is("LINES_ARRAY:SP", tpar_file.read())
 
-    def test_tpar_missing_file_gives_warning(self):
-        file_name = "tpar.tpar"
-        self.ca.set_pv_value("FILE_NAME:SP", file_name)
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "No")
-        self.ca.set_pv_value("FILE_NAME:SP", "missing_file.txt")
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "Yes")
-
     def test_tpar_editor_writes_tpar_content(self):
-        file_name = TEST_TPAR_FILENAME
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "No")
-        self.ca.set_pv_value("FILE_NAME:SP", file_name, wait=True)
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "Yes")
         self.ca.set_pv_value("LINES_ARRAY:SP", TEST_TPAR)
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "Yes")
-        with ManagerMode(ChannelAccess()):
-            self.ca.set_pv_value("SAVE_FILE", 1, wait=True)
+        self.ca.set_pv_value("SAVE_FILE", 1, wait=True)
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "No")
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "No")
-        with open(os.path.join(test_config_path, file_name), "r") as tpar_file:
+        with open(test_config_path / DEFAULT_OUTPUT_FILE, "r") as tpar_file:
             self.assertEqual(TEST_TPAR, tpar_file.read())
 
     def test_tpar_editor_reset(self):
-        file_name = "tpar.tpar"
-        self.ca.set_pv_value("FILE_NAME:SP", file_name, wait=True)
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "No")
-        self.ca.assert_that_pv_is("NEW_FILE_WARNING", "No")
         self.ca.set_pv_value("LINES_ARRAY:SP", TEST_TPAR)
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "Yes")
         self.ca.set_pv_value("RESET", 1)
         self.ca.assert_that_pv_is("UNSAVED_CHANGES", "No")
-        with open(os.path.join(test_config_path, file_name), "r") as tpar_file:
+        with open(test_config_path / DEFAULT_OUTPUT_FILE, "r") as tpar_file:
             self.ca.assert_that_pv_is("LINES_ARRAY:SP", tpar_file.read())