diff --git a/CHANGES.md b/CHANGES.md
index 8d87704e..f916911c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -7,6 +7,9 @@
 - fix Component.require_one raising a configuration error with strict=False
 - Adds command `./batou secrets decrypttostdout` to decrypt a secrets file to stdout.
   - Useful for integration with git diff using textconv, see documentation for installation instructions.
+- The error message shown when a batou deployment fails to start due to another
+  deployment running at the same time, now correctly informs the user that
+  another deployment is running instead of showing a traceback. (#446)
 
 
 ## 2.5.0 (2024-09-04)
diff --git a/src/batou/deploy.py b/src/batou/deploy.py
index c8e62d1c..933cd85d 100644
--- a/src/batou/deploy.py
+++ b/src/batou/deploy.py
@@ -361,7 +361,7 @@ def main(
     else:
         ACTION = "DEPLOYMENT"
         SUCCESS_FORMAT = {"green": True}
-    with locked(".batou-lock"):
+    with locked(".batou-lock", exit_on_failure=True):
         deployment = Deployment(
             environment,
             platform,
diff --git a/src/batou/utils.py b/src/batou/utils.py
index 7ce3b2b5..bf1e6299 100644
--- a/src/batou/utils.py
+++ b/src/batou/utils.py
@@ -64,13 +64,20 @@ def flush(self):
 
 
 @contextlib.contextmanager
-def locked(filename):
+def locked(filename, exit_on_failure=False):
     # XXX can we make this not leave files around?
     with open(filename, "a+") as lockfile:
         try:
             fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
         except IOError:
             print("Could not acquire lock {}".format(filename), file=sys.stderr)
+            if exit_on_failure:
+                print(
+                    "Another instance of batou is currently running and locked the lockfile.",
+                    file=sys.stderr,
+                )
+                print("Exiting.", file=sys.stderr)
+                sys.exit(1)
             raise RuntimeError(
                 'cannot create lock "%s": more than one instance running '
                 "concurrently?" % lockfile,