diff --git a/src/octoprint/filemanager/storage.py b/src/octoprint/filemanager/storage.py
index 8cd24d38cf..aa5a8863fc 100644
--- a/src/octoprint/filemanager/storage.py
+++ b/src/octoprint/filemanager/storage.py
@@ -954,6 +954,12 @@ def copy_file(self, source, destination):
             source, destination, must_not_equal=True
         )
 
+        if not octoprint.filemanager.valid_file_type(destination_data["name"]):
+            raise StorageError(
+                f"{destination_data['name']} is an unrecognized file type",
+                code=StorageError.INVALID_FILE,
+            )
+
         try:
             shutil.copy2(source_data["fullpath"], destination_data["fullpath"])
         except Exception as e:
@@ -983,6 +989,12 @@ def move_file(self, source, destination, allow_overwrite=False):
             source, destination
         )
 
+        if not octoprint.filemanager.valid_file_type(destination_data["name"]):
+            raise StorageError(
+                f"{destination_data['name']} is an unrecognized file type",
+                code=StorageError.INVALID_FILE,
+            )
+
         # only a display rename? Update that and bail early
         if source_data["fullpath"] == destination_data["fullpath"]:
             self._set_display_metadata(destination_data)
diff --git a/src/octoprint/server/__init__.py b/src/octoprint/server/__init__.py
index 6f095aa150..b4a6c84d9c 100644
--- a/src/octoprint/server/__init__.py
+++ b/src/octoprint/server/__init__.py
@@ -40,6 +40,7 @@
 from watchdog.observers.polling import PollingObserver
 from werkzeug.exceptions import HTTPException
 
+import octoprint.filemanager
 import octoprint.util
 import octoprint.util.net
 from octoprint.server import util
@@ -746,6 +747,15 @@ def download_name_generator(path):
             )
         }
 
+        only_known_types_validator = {
+            "path_validation": util.tornado.path_validation_factory(
+                lambda path: octoprint.filemanager.valid_file_type(
+                    os.path.basename(path)
+                ),
+                status_code=404,
+            )
+        }
+
         valid_timelapse = lambda path: not octoprint.util.is_hidden_path(path) and (
             octoprint.timelapse.valid_timelapse(path)
             or octoprint.timelapse.valid_timelapse_thumbnail(path)
@@ -840,6 +850,7 @@ def joined_dict(*dicts):
                     download_permission_validator,
                     download_handler_kwargs,
                     no_hidden_files_validator,
+                    only_known_types_validator,
                     additional_mime_types,
                 ),
             ),
diff --git a/src/octoprint/server/api/files.py b/src/octoprint/server/api/files.py
index 35c8b4da9c..40e6200c98 100644
--- a/src/octoprint/server/api/files.py
+++ b/src/octoprint/server/api/files.py
@@ -1138,42 +1138,55 @@ def slicing_done(target, path, select_after_slicing, print_after_slicing):
             if not (is_file or is_folder):
                 abort(400, description=f"Neither file nor folder, can't {command}")
 
-            if command == "copy":
-                # destination already there? error...
-                if _verifyFileExists(target, destination) or _verifyFolderExists(
-                    target, destination
-                ):
-                    abort(409, description="File or folder does already exist")
-
-                if is_file:
-                    fileManager.copy_file(target, filename, destination)
-                else:
-                    fileManager.copy_folder(target, filename, destination)
-
-            elif command == "move":
-                with Permissions.FILES_DELETE.require(403):
-                    if _isBusy(target, filename):
-                        abort(
-                            409,
-                            description="Trying to move a file or folder that is currently in use",
-                        )
-
-                    # destination already there AND not ourselves (= display rename)? error...
-                    if (
-                        _verifyFileExists(target, destination)
-                        or _verifyFolderExists(target, destination)
-                    ) and sanitized_destination != filename:
+            try:
+                if command == "copy":
+                    # destination already there? error...
+                    if _verifyFileExists(target, destination) or _verifyFolderExists(
+                        target, destination
+                    ):
                         abort(409, description="File or folder does already exist")
 
-                    # deselect the file if it's currently selected
-                    currentOrigin, currentFilename = _getCurrentFile()
-                    if currentFilename is not None and filename == currentFilename:
-                        printer.unselect_file()
-
                     if is_file:
-                        fileManager.move_file(target, filename, destination)
+                        fileManager.copy_file(target, filename, destination)
                     else:
-                        fileManager.move_folder(target, filename, destination)
+                        fileManager.copy_folder(target, filename, destination)
+
+                elif command == "move":
+                    with Permissions.FILES_DELETE.require(403):
+                        if _isBusy(target, filename):
+                            abort(
+                                409,
+                                description="Trying to move a file or folder that is currently in use",
+                            )
+
+                        # destination already there AND not ourselves (= display rename)? error...
+                        if (
+                            _verifyFileExists(target, destination)
+                            or _verifyFolderExists(target, destination)
+                        ) and sanitized_destination != filename:
+                            abort(409, description="File or folder does already exist")
+
+                        # deselect the file if it's currently selected
+                        currentOrigin, currentFilename = _getCurrentFile()
+                        if currentFilename is not None and filename == currentFilename:
+                            printer.unselect_file()
+
+                        if is_file:
+                            fileManager.move_file(target, filename, destination)
+                        else:
+                            fileManager.move_folder(target, filename, destination)
+
+            except octoprint.filemanager.storage.StorageError as e:
+                if e.code == octoprint.filemanager.storage.StorageError.INVALID_FILE:
+                    abort(
+                        415,
+                        description=f"Could not {command} {filename} to {destination}, invalid type",
+                    )
+                else:
+                    abort(
+                        500,
+                        description=f"Could not {command} {filename} to {destination}",
+                    )
 
             location = url_for(
                 ".readGcodeFile",