diff --git a/k4FWCore/scripts/k4run b/k4FWCore/scripts/k4run
index 30d8c713..f9c724ec 100755
--- a/k4FWCore/scripts/k4run
+++ b/k4FWCore/scripts/k4run
@@ -86,6 +86,10 @@ def add_arguments(parser, app_mgr):
             if proptype is list:
                 if value:
                     proptype = type(value[0])
+                # If the list is empty, we can't determine the type
+                # Assume it's a string by default and hope it will work
+                else:
+                    proptype = str
                 args = "+"
 
             # add the argument twice, once as "--PodioOutput.filename"
diff --git a/test/k4FWCoreTest/CMakeLists.txt b/test/k4FWCoreTest/CMakeLists.txt
index 5ea6d555..34ed2fc2 100644
--- a/test/k4FWCoreTest/CMakeLists.txt
+++ b/test/k4FWCoreTest/CMakeLists.txt
@@ -174,6 +174,8 @@ add_test_with_env(FunctionalNonExistingFileOverwritten options/ExampleFunctional
 add_test_with_env(FunctionalFileTooLong options/ExampleFunctionalFile.py -n 999 --IOSvc.Output toolong.root PROPERTIES PASS_REGULAR_EXPRESSION
                   "Application Manager Terminated successfully with a user requested ScheduledStop")
 add_test_with_env(FunctionalFileTooShort options/ExampleFunctionalFile.py -n 2 --IOSvc.Output two_events.root ADD_TO_CHECK_FILES)
+add_test_with_env(FunctionalFileCLI options/ExampleFunctionalNoFile.py --IOSvc.Input functional_producer.root --IOSvc.Output functional_transformer_cli.root ADD_TO_CHECK_FILES)
+set_tests_properties(FunctionalFileCLI PROPERTIES DEPENDS FunctionalProducer)
 
 add_test_with_env(FunctionalWrongImport options/ExampleFunctionalWrongImport.py)
 set_tests_properties(FunctionalWrongImport PROPERTIES PASS_REGULAR_EXPRESSION "ImportError: Importing ApplicationMgr or IOSvc from Configurables is not allowed.")
diff --git a/test/k4FWCoreTest/options/ExampleFunctionalNoFile.py b/test/k4FWCoreTest/options/ExampleFunctionalNoFile.py
new file mode 100644
index 00000000..4225b849
--- /dev/null
+++ b/test/k4FWCoreTest/options/ExampleFunctionalNoFile.py
@@ -0,0 +1,40 @@
+#
+# Copyright (c) 2014-2024 Key4hep-Project.
+#
+# This file is part of Key4hep.
+# See https://key4hep.github.io/key4hep-doc/ for further info.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# This is an example reading from a file and using a transformer to create new
+# data
+
+from Gaudi.Configuration import INFO
+from Configurables import ExampleFunctionalTransformer
+from Configurables import EventDataSvc
+from k4FWCore import ApplicationMgr, IOSvc
+
+svc = IOSvc("IOSvc")
+
+transformer = ExampleFunctionalTransformer(
+    "Transformer", InputCollection=["MCParticles"], OutputCollection=["NewMCParticles"]
+)
+
+mgr = ApplicationMgr(
+    TopAlg=[transformer],
+    EvtSel="NONE",
+    EvtMax=-1,
+    ExtSvc=[EventDataSvc("EventDataSvc")],
+    OutputLevel=INFO,
+)
diff --git a/test/k4FWCoreTest/scripts/CheckOutputFiles.py b/test/k4FWCoreTest/scripts/CheckOutputFiles.py
index 14b23e85..00c60bdb 100644
--- a/test/k4FWCoreTest/scripts/CheckOutputFiles.py
+++ b/test/k4FWCoreTest/scripts/CheckOutputFiles.py
@@ -70,6 +70,7 @@ def check_metadata(filename, expected_metadata):
 
 
 check_collections("functional_transformer.root", ["MCParticles", "NewMCParticles"])
+check_collections("functional_transformer_cli.root", ["MCParticles", "NewMCParticles"])
 check_collections(
     "functional_transformer_multiple.root",
     [