Windows Native Toolkit | File System Library

Use this library for safe Windows file-system operations. Destructive actions validate empty paths, drive roots, Windows system folders, invalid names, and source or destination mistakes before the operation runs.

Python examples use Unreal's reflected API names through the unreal module. Async file-operation nodes stay C++-only here because their delegate-driven execution model is not practical to run from Unreal Python.

Async File Operations

Move File To Path, Move Folder To Path, Copy File To Path, Copy Folder To Path, Delete File, Delete Folder, Recycle File, Recycle Folder, Rename File, and Rename Folder are async action nodes. In Blueprint they give an immediate Then continuation pin plus direct On Success and On Fail exec pins.

Failure Reporting

Public error-message pins were removed. When a node fails, it uses the On Fail pin for Blueprint flow and writes the detailed reason with UE_LOG(Error, ...).

Move File To Path

Moves one file into a destination folder on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Context used to register the async action with the game instance.
`Source`	Input	Full path to the source file.
`Destination`	Input	Target folder path.
`bOverwrite`	Input	Allows the destination file to be replaced when it already exists.
`Then`	Output	Continues immediately after the async action is created.
`On Success`	Output	Fires when the move completes successfully.
`On Fail`	Output	Fires when validation or the move operation fails.

C++ Example

#include "FileSystemLibrary.h"

UFUNCTION()
void HandleFileOperationSuccess();

UFUNCTION()
void HandleFileOperationFail();

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::MoveFileToFolder(this, SourcePath, DestinationFolder, true);

Operation->OnSuccess.AddDynamic(this, &UMyObject::HandleFileOperationSuccess);
Operation->OnFail.AddDynamic(this, &UMyObject::HandleFileOperationFail);

Move Folder To Path

Moves one folder into another folder on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`Source`	Input	Full path to the source folder.
`Destination`	Input	Target parent folder path.
`bOverwrite`	Input	Allows overwriting an existing target folder.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the move succeeds.
`On Fail`	Output	Fires when validation or the move fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::MoveFolderToFolder(this, SourceFolder, DestinationFolder, false);

Copy File To Path

Copies one file into a destination folder on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`Source`	Input	Full path to the source file.
`Destination`	Input	Target folder path.
`bOverwrite`	Input	Allows replacing an existing destination file.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the copy succeeds.
`On Fail`	Output	Fires when validation or the copy fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::CopyFileToFolder(this, SourcePath, DestinationFolder, true);

Copy Folder To Path

Copies one folder tree into a destination folder on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`Source`	Input	Full path to the source folder.
`Destination`	Input	Target parent folder path.
`bOverwrite`	Input	Allows replacing an existing destination folder.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the copy succeeds.
`On Fail`	Output	Fires when validation or the copy fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::CopyFolderToFolder(this, SourceFolder, DestinationFolder, true);

Delete File

Permanently deletes one file on a background thread after path safety checks.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`Path`	Input	Full path to the file to delete.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the file is deleted.
`On Fail`	Output	Fires when validation or deletion fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::DeleteFileW(this, FilePath);

Delete Folder

Permanently deletes one folder tree on a background thread after path safety checks.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`Path`	Input	Full path to the folder to delete.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the folder is deleted.
`On Fail`	Output	Fires when validation or deletion fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::DeleteFolder(this, FolderPath);

Recycle File

Moves one file to the Windows Recycle Bin instead of deleting it permanently.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`FilePath`	Input	Full path to the file to recycle.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when Windows accepts the recycle request.
`On Fail`	Output	Fires when validation or the recycle request fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::RecycleFile(this, FilePath);

Recycle Folder

Moves one folder to the Windows Recycle Bin instead of deleting it permanently.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`FolderPath`	Input	Full path to the folder to recycle.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when Windows accepts the recycle request.
`On Fail`	Output	Fires when validation or the recycle request fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::RecycleFolder(this, FolderPath);

Rename File

Renames a file in place on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`FilePath`	Input	Full path to the existing file.
`NewFileName`	Input	New file name. Include the extension when the file should keep one.
`bOverwrite`	Input	Allows replacing an existing file with the same target name.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the rename succeeds.
`On Fail`	Output	Fires when validation or the rename fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::RenameFile(this, FilePath, TEXT("Renamed.txt"), true);

Rename Folder

Renames a folder in place on a background thread.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`FolderPath`	Input	Full path to the existing folder.
`NewFolderName`	Input	New folder name only, not a full path.
`bOverwrite`	Input	Allows replacing an existing folder with the same target name.
`Then`	Output	Continues immediately after the node starts.
`On Success`	Output	Fires when the rename succeeds.
`On Fail`	Output	Fires when validation or the rename fails.

C++ Example

#include "FileSystemLibrary.h"

UAsyncFileSystemOperation* Operation =
    UAsyncFileSystemOperation::RenameFolder(this, FolderPath, TEXT("RenamedFolder"), true);

Get File Info

Returns metadata for one file path.

Pin	Direction	Purpose
`FilePath`	Input	File path to inspect.
`Return Value`	Output	`FWNTFileInfo` containing file-specific metadata.

FWNTFileInfo fields:

bExists
AbsolutePath
FileName
Extension
bIsReadOnly
FileSizeBytes
CreationTime
AccessTime
ModificationTime

C++ Example

#include "FileSystemLibrary.h"

const FWNTFileInfo Info = UFileSystemLibrary::GetFileInfo(FilePath);

Python Example

import unreal

info = unreal.FileSystemLibrary.get_file_info(file_path)

Get Folder Info

Returns metadata for one folder path.

Pin	Direction	Purpose
`FolderPath`	Input	Folder path to inspect.
`Return Value`	Output	`FWNTFolderInfo` containing folder-specific metadata.

FWNTFolderInfo fields:

bExists
AbsolutePath
FolderName
ParentPath
bIsReadOnly
CreationTime
AccessTime
ModificationTime

The folder struct intentionally does not include size. Use Get Folder Size for size queries.

C++ Example

#include "FileSystemLibrary.h"

const FWNTFolderInfo Info = UFileSystemLibrary::GetFolderInfo(FolderPath);

Python Example

import unreal

info = unreal.FileSystemLibrary.get_folder_info(folder_path)

Get Folder Size

Calculates folder size asynchronously and can report progress while the scan runs.

Pin	Direction	Purpose
`WorldContextObject`	Input	Async action registration context.
`FolderPath`	Input	Folder path to scan recursively.
`Then`	Output	Continues immediately after the node starts.
`On Progress`	Output	Reports the current accumulated size in bytes while scanning.
`On Success`	Output	Reports the final folder size in bytes.
`On Fail`	Output	Fires when validation fails, the scan fails, or the scan is canceled.

C++ Example

#include "FileSystemLibrary.h"

UFUNCTION()
void HandleFolderSizeProgress(int64 FolderSizeBytes);

UFUNCTION()
void HandleFolderSizeSuccess(int64 FolderSizeBytes);

UFUNCTION()
void HandleFolderSizeFail(int64 FolderSizeBytes);

UAsyncGetFolderSize* Operation = UAsyncGetFolderSize::GetFolderSize(this, FolderPath);
Operation->OnProgress.AddDynamic(this, &UMyObject::HandleFolderSizeProgress);
Operation->OnSuccess.AddDynamic(this, &UMyObject::HandleFolderSizeSuccess);
Operation->OnFail.AddDynamic(this, &UMyObject::HandleFolderSizeFail);

Show File In Explorer

Opens Windows Explorer and selects the specified file or folder.

Pin	Direction	Purpose
`FilePath`	Input	File or folder path to reveal in Explorer.

C++ Example

#include "FileSystemLibrary.h"

UFileSystemLibrary::ShowFileInExplorer(FilePath);

Python Example

import unreal

unreal.FileSystemLibrary.show_file_in_explorer(file_path)

Get Drives

Returns available Windows drives and basic capacity information.

Pin	Direction	Purpose
`Return Value`	Output	`TArray<FPartitionInfo>` with drive identity and capacity details.

FPartitionInfo fields:

DriveLetter
VolumeLabel
FileSystem
DriveType
bIsSystemPartition
TotalSizeBytes
FreeSizeBytes
UsedSizeBytes

C++ Example

#include "FileSystemLibrary.h"

const TArray<FPartitionInfo> Drives = UFileSystemLibrary::GetAllAvailablePartitions();

Python Example

import unreal

drives = unreal.FileSystemLibrary.get_all_available_partitions()

File System Library

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