diff --git a/src/primaite/simulator/file_system/file_system.py b/src/primaite/simulator/file_system/file_system.py
index 3290570e..d42db3e0 100644
--- a/src/primaite/simulator/file_system/file_system.py
+++ b/src/primaite/simulator/file_system/file_system.py
@@ -69,6 +69,10 @@ class FileSystem(SimComponent):
             folder = self.get_folder_by_id(folder_uuid)
 
         if folder is not None:
+            # check if file with name already exists
+            if folder.get_file_by_name(file_name):
+                raise Exception(f'File with name "{file_name}" already exists.')
+
             file = FileSystemFile(name=file_name, size=size, file_type=file_type)
             folder.add_file(file=file)
         else:
@@ -94,7 +98,12 @@ class FileSystem(SimComponent):
         :param: folder_name: The name of the folder
         :type: folder_name: str
         """
+        # check if folder with name already exists
+        if self.get_folder_by_name(folder_name):
+            raise Exception(f'Folder with name "{folder_name}" already exists.')
+
         folder = FileSystemFolder(name=folder_name)
+
         self.folders[folder.uuid] = folder
         return folder
 
@@ -149,6 +158,10 @@ class FileSystem(SimComponent):
         if file is None:
             raise Exception("File to be moved is None")
 
+        # check if file with name already exists
+        if target_folder.get_file_by_name(file.name):
+            raise Exception(f'Folder with name "{file.name}" already exists.')
+
         # remove file from src
         src_folder.remove_file(file)
 
@@ -179,6 +192,10 @@ class FileSystem(SimComponent):
         if file is None:
             raise Exception("File to be moved is None")
 
+        # check if file with name already exists
+        if target_folder.get_file_by_name(file.name):
+            raise Exception(f'Folder with name "{file.name}" already exists.')
+
         # add file to target
         target_folder.add_file(file)
 
diff --git a/src/primaite/simulator/file_system/file_system_folder.py b/src/primaite/simulator/file_system/file_system_folder.py
index 79e19189..b0705804 100644
--- a/src/primaite/simulator/file_system/file_system_folder.py
+++ b/src/primaite/simulator/file_system/file_system_folder.py
@@ -20,14 +20,22 @@ class FileSystemFolder(FileSystemItem):
         """Return a FileSystemFile with the matching id."""
         return self.files.get(file_id)
 
+    def get_file_by_name(self, file_name: str) -> FileSystemFile:
+        """Return a FileSystemFile with the matching id."""
+        return next((f for f in list(self.files) if f.name == file_name), None)
+
     def add_file(self, file: FileSystemFile):
         """Adds a file to the folder list."""
         if file is None or not isinstance(file, FileSystemFile):
             raise Exception(f"Invalid file: {file}")
 
-        # add to list
-        self.files[file.uuid] = file
-        self.size += file.size
+        # check if file with id already exists in folder
+        if file.uuid in self.files:
+            _LOGGER.debug(f"File with id {file.uuid} already exists in folder")
+        else:
+            # add to list
+            self.files[file.uuid] = file
+            self.size += file.size
 
     def remove_file(self, file: Optional[FileSystemFile]):
         """
diff --git a/tests/unit_tests/_primaite/_simulator/_file_system/test_file_system.py b/tests/unit_tests/_primaite/_simulator/_file_system/test_file_system.py
index 5bebf487..348eb440 100644
--- a/tests/unit_tests/_primaite/_simulator/_file_system/test_file_system.py
+++ b/tests/unit_tests/_primaite/_simulator/_file_system/test_file_system.py
@@ -1,4 +1,5 @@
 from primaite.simulator.file_system.file_system import FileSystem
+from primaite.simulator.file_system.file_system_file import FileSystemFile
 from primaite.simulator.file_system.file_system_folder import FileSystemFolder
 
 
@@ -37,7 +38,7 @@ def test_delete_file():
 
     file_system.delete_file(file=file)
     assert len(file_system.folders) is 1
-    assert len(file_system.get_folder_by_id(folder.uuid).files) is 0
+    assert len(folder.files) is 0
 
 
 def test_delete_non_existent_file():
@@ -45,16 +46,20 @@ def test_delete_non_existent_file():
     file_system = FileSystem()
 
     file = file_system.create_file(file_name="test_file", size=10)
-    not_added_file = file_system.create_file(file_name="test_file", size=10)
+    not_added_file = FileSystemFile(name="not_added")
+    # folder should be created
     assert len(file_system.folders) is 1
-
+    # should only have 1 file in the file system
     folder_id = list(file_system.folders.keys())[0]
     folder = file_system.get_folder_by_id(folder_id)
+    assert len(list(folder.files)) is 1
+
     assert folder.get_file_by_id(file.uuid) is file
 
+    # deleting should not change how many files are in folder
     file_system.delete_file(file=not_added_file)
     assert len(file_system.folders) is 1
-    assert len(file_system.get_folder_by_id(folder.uuid).files) is 1
+    assert len(list(folder.files)) is 1
 
 
 def test_delete_folder():