diff --git a/invokeai/app/services/object_serializer/object_serializer_disk.py b/invokeai/app/services/object_serializer/object_serializer_disk.py
index 935fec30605..8edd29e1505 100644
--- a/invokeai/app/services/object_serializer/object_serializer_disk.py
+++ b/invokeai/app/services/object_serializer/object_serializer_disk.py
@@ -1,6 +1,6 @@
+import shutil
 import tempfile
 import typing
-from dataclasses import dataclass
 from pathlib import Path
 from typing import TYPE_CHECKING, Optional, TypeVar
 
@@ -17,12 +17,6 @@
 T = TypeVar("T")
 
 
-@dataclass
-class DeleteAllResult:
-    deleted_count: int
-    freed_space_bytes: float
-
-
 class ObjectSerializerDisk(ObjectSerializerBase[T]):
     """Disk-backed storage for arbitrary python objects. Serialization is handled by `torch.save` and `torch.load`.
 
@@ -35,6 +29,12 @@ def __init__(self, output_dir: Path, ephemeral: bool = False):
         self._ephemeral = ephemeral
         self._base_output_dir = output_dir
         self._base_output_dir.mkdir(parents=True, exist_ok=True)
+
+        if self._ephemeral:
+            # Remove dangling tempdirs that might have been left over from an earlier unplanned shutdown.
+            for temp_dir in filter(Path.is_dir, self._base_output_dir.glob("tmp*")):
+                shutil.rmtree(temp_dir)
+
         # Must specify `ignore_cleanup_errors` to avoid fatal errors during cleanup on Windows
         self._tempdir = (
             tempfile.TemporaryDirectory(dir=self._base_output_dir, ignore_cleanup_errors=True) if ephemeral else None
diff --git a/tests/test_object_serializer_disk.py b/tests/test_object_serializer_disk.py
index 125534c5002..84c6e876fcb 100644
--- a/tests/test_object_serializer_disk.py
+++ b/tests/test_object_serializer_disk.py
@@ -99,6 +99,20 @@ def test_obj_serializer_ephemeral_writes_to_tempdir(tmp_path: Path):
     assert not Path(tmp_path, obj_1_name).exists()
 
 
+def test_obj_serializer_ephemeral_deletes_dangling_tempdirs_on_init(tmp_path: Path):
+    tempdir = tmp_path / "tmpdir"
+    tempdir.mkdir()
+    ObjectSerializerDisk[MockDataclass](tmp_path, ephemeral=True)
+    assert not tempdir.exists()
+
+
+def test_obj_serializer_does_not_delete_tempdirs_on_init(tmp_path: Path):
+    tempdir = tmp_path / "tmpdir"
+    tempdir.mkdir()
+    ObjectSerializerDisk[MockDataclass](tmp_path, ephemeral=False)
+    assert tempdir.exists()
+
+
 def test_obj_serializer_disk_different_types(tmp_path: Path):
     obj_serializer_1 = ObjectSerializerDisk[MockDataclass](tmp_path)
     obj_1 = MockDataclass(foo="bar")