Workaround for Windows being unable to remove tmp directories when installing GGUF files (#8699)

* (bugfix)(mm) work around Windows being unable to rmtree tmp directories after GGUF install

* (style) fix ruff error

* (fix) add workaround for Windows Permission Denied on GGUF file move() call

* (fix) perform torch copy() in GGUF reader to avoid deletion failures on Windows

* (style) fix ruff formatting issues

Author: lstein

invokeai/app/services/model_install/model_install_default.py

@@ -1,8 +1,10 @@
 """Model installation class."""
 
+import gc
 import locale
 import os
 import re
+import sys
 import threading
 import time
 from copy import deepcopy
@@ -187,6 +189,22 @@ def register_path(
         config.source_type = ModelSourceType.Path
         return self._register(model_path, config)
 
+    # TODO: Replace this with a proper fix for underlying problem of Windows holding open
+    # the file when it needs to be moved.
+    @staticmethod
+    def _move_with_retries(src: Path, dst: Path, attempts: int = 5, delay: float = 0.5) -> None:
+        """Workaround for Windows file-handle issues when moving files."""
+        for tries_left in range(attempts, 0, -1):
+            try:
+                move(src, dst)
+                return
+            except PermissionError:
+                gc.collect()
+                if tries_left == 1:
+                    raise
+                time.sleep(delay)
+                delay *= 2  # Exponential backoff
+
     def install_path(
         self,
         model_path: Union[Path, str],
@@ -205,7 +223,7 @@ def install_path(
             dest_dir.mkdir(parents=True)
             dest_path = dest_dir / model_path.name if model_path.is_file() else dest_dir
             if model_path.is_file():
-                move(model_path, dest_path)
+                self._move_with_retries(model_path, dest_path)  # Windows workaround TODO: fix root cause
             elif model_path.is_dir():
                 # Move the contents of the directory, not the directory itself
                 for item in model_path.iterdir():
@@ -500,6 +518,39 @@ def _start_installer_thread(self) -> None:
         self._install_thread.start()
         self._running = True
 
+    @staticmethod
+    def _safe_rmtree(path: Path, logger: Any) -> None:
+        """Remove a directory tree with retry logic for Windows file locking issues.
+
+        On Windows, memory-mapped files may not be immediately released even after
+        the file handle is closed. This function retries the removal with garbage
+        collection to help release any lingering references.
+        """
+        max_retries = 3
+        retry_delay = 0.5  # seconds
+
+        for attempt in range(max_retries):
+            try:
+                # Force garbage collection to release any lingering file references
+                gc.collect()
+                rmtree(path)
+                return
+            except PermissionError as e:
+                if attempt < max_retries - 1 and sys.platform == "win32":
+                    logger.warning(
+                        f"Failed to remove {path} (attempt {attempt + 1}/{max_retries}): {e}. "
+                        f"Retrying in {retry_delay}s..."
+                    )
+                    time.sleep(retry_delay)
+                    retry_delay *= 2  # Exponential backoff
+                else:
+                    logger.error(f"Failed to remove temporary directory {path}: {e}")
+                    # On final failure, don't raise - the temp dir will be cleaned up on next startup
+                    return
+            except Exception as e:
+                logger.error(f"Unexpected error removing {path}: {e}")
+                return
+
     def _install_next_item(self) -> None:
         self._logger.debug(f"Installer thread {threading.get_ident()} starting")
         while True:
@@ -529,7 +580,7 @@ def _install_next_item(self) -> None:
             finally:
                 # if this is an install of a remote file, then clean up the temporary directory
                 if job._install_tmpdir is not None:
-                    rmtree(job._install_tmpdir)
+                    self._safe_rmtree(job._install_tmpdir, self._logger)
                 self._install_completed_event.set()
                 self._install_queue.task_done()
         self._logger.info(f"Installer thread {threading.get_ident()} exiting")
@@ -574,7 +625,7 @@ def _remove_dangling_install_dirs(self) -> None:
         path = self._app_config.models_path
         for tmpdir in path.glob(f"{TMPDIR_PREFIX}*"):
             self._logger.info(f"Removing dangling temporary directory {tmpdir}")
-            rmtree(tmpdir)
+            self._safe_rmtree(tmpdir, self._logger)
 
     def _scan_for_missing_models(self) -> list[AnyModelConfig]:
         """Scan the models directory for missing models and return a list of them."""

invokeai/backend/quantization/gguf/loaders.py

@@ -40,7 +40,11 @@ def gguf_sd_loader(path: Path, compute_dtype: torch.dtype) -> dict[str, GGMLTens
     with WrappedGGUFReader(path) as reader:
         sd: dict[str, GGMLTensor] = {}
         for tensor in reader.tensors:
-            torch_tensor = torch.from_numpy(tensor.data)
+            # Use .copy() to create a true copy of the data, not a view.
+            # This is critical on Windows where the memory-mapped file cannot be deleted
+            # while tensors still hold references to the mapped memory.
+            torch_tensor = torch.from_numpy(tensor.data.copy())
+
             shape = torch.Size(tuple(int(v) for v in reversed(tensor.shape)))
             if tensor.tensor_type in TORCH_COMPATIBLE_QTYPES:
                 torch_tensor = torch_tensor.view(*shape)