diff --git a/pycromanager/_version.py b/pycromanager/_version.py
index 5829d673..03d6b15b 100644
--- a/pycromanager/_version.py
+++ b/pycromanager/_version.py
@@ -1,2 +1,2 @@
-version_info = (0, 28, 1)
+version_info = (0, 28, 2)
 __version__ = ".".join(map(str, version_info))
diff --git a/pycromanager/acq_util.py b/pycromanager/acq_util.py
index fb07fbd2..3a352c3f 100644
--- a/pycromanager/acq_util.py
+++ b/pycromanager/acq_util.py
@@ -11,13 +11,14 @@
 
 SUBPROCESSES = []
 
-def cleanup():
+def stop_headless():
     for p in SUBPROCESSES:
         p.terminate()
         p.wait()  # wait for process to terminate
+    SUBPROCESSES.clear()
 
 # make sure any Java processes are cleaned up when Python exits
-atexit.register(cleanup)
+atexit.register(stop_headless)
 
 def start_headless(
     mm_app_path: str, config_file: str='', java_loc: str=None, core_log_path: str='',
diff --git a/pycromanager/test/conftest.py b/pycromanager/test/conftest.py
index 8962f966..4a37a908 100644
--- a/pycromanager/test/conftest.py
+++ b/pycromanager/test/conftest.py
@@ -10,7 +10,7 @@
 
 import pycromanager
 from pycromanager import start_headless
-from pycromanager.acq_util import cleanup
+from pycromanager.acq_util import stop_headless
 import socket
 
 def is_port_in_use(port):