diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index 770f9a80..d10e7f10 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -315,7 +315,7 @@ def run_argparse(argv, formatter):
     ap2.add_argument("--th-no-webp", action="store_true", help="disable webp output")
     ap2.add_argument("--th-ff-jpg", action="store_true", help="force jpg for video thumbs")
     ap2.add_argument("--th-poke", metavar="SEC", type=int, default=300, help="activity labeling cooldown")
-    ap2.add_argument("--th-clean", metavar="SEC", type=int, default=43200, help="cleanup interval")
+    ap2.add_argument("--th-clean", metavar="SEC", type=int, default=43200, help="cleanup interval; 0=disabled")
     ap2.add_argument("--th-maxage", metavar="SEC", type=int, default=604800, help="max folder age")
     ap2.add_argument("--th-covers", metavar="N,N", type=str, default="folder.png,folder.jpg,cover.png,cover.jpg", help="folder thumbnails to stat for")
 
diff --git a/copyparty/th_srv.py b/copyparty/th_srv.py
index 113875f8..d4324def 100644
--- a/copyparty/th_srv.py
+++ b/copyparty/th_srv.py
@@ -130,9 +130,10 @@ class ThumbSrv(object):
             msg += ", ".join(missing)
             self.log(msg, c=3)
 
-        t = threading.Thread(target=self.cleaner, name="thumb-cleaner")
-        t.daemon = True
-        t.start()
+        if self.args.th_clean:
+            t = threading.Thread(target=self.cleaner, name="thumb-cleaner")
+            t.daemon = True
+            t.start()
 
     def log(self, msg, c=0):
         self.log_func("thumb", msg, c)