File access permissions

Universal Windows Platform (UWP) apps can access certain file system locations by default. Apps can also access additional locations through the file picker, or by declaring capabilities.

Locations that all apps can access

When you create a new app, you can access the following file system locations by default:

Application install directory

The folder where your app is installed on the user’s system.

There are two primary ways to access files and folders in your app’s install directory:

You can retrieve a StorageFolder that represents your app’s install directory, like this:

You can then access files and folders in the directory using StorageFolder methods. In the example, this StorageFolder is stored in the installDirectory variable. You can learn more about working with your app package and install directory from the App package information sample on GitHub.

You can retrieve a file directly from your app’s install directory by using an app URI, like this:

When GetFileFromApplicationUriAsync completes, it returns a StorageFile that represents the file.txt file in the app’s install directory ( file in the example).

The «ms-appx:///» prefix in the URI refers to the app’s install directory. You can learn more about using app URIs in How to use URIs to reference content.

In addition, and unlike other locations, you can also access files in your app install directory by using some Win32 and COM for Universal Windows Platform (UWP) apps and some C/C++ Standard Library functions from Microsoft Visual Studio.

The app’s install directory is a read-only location. You can’t gain access to the install directory through the file picker.

Application data locations

The folders where your app can store data. These folders (local, roaming and temporary) are created when your app is installed.

There are two primary ways to access files and folders from your app’s data locations:

Use ApplicationData properties to retrieve an app data folder.

For example, you can use ApplicationData.LocalFolder to retrieve a StorageFolder that represents your app’s local folder like this:

If you want to access your app’s roaming or temporary folder, use the RoamingFolder or TemporaryFolder property instead.

After you retrieve a StorageFolder that represents an app data location, you can access files and folders in that location by using StorageFolder methods. In the example, these StorageFolder objects are stored in the localFolder variable. You can learn more about using app data locations from the guidance on the ApplicationData class page, and by downloading the Application data sample from GitHub.

You can retrieve a file directly from your app’s local folder by using an app URI, like this:

When GetFileFromApplicationUriAsync completes, it returns a StorageFile that represents the file.txt file in the app’s local folder ( file in the example).

The «ms-appdata:///local/» prefix in the URI refers to the app’s local folder. To access files in the app’s roaming or temporary folders use «ms-appdata:///roaming/» or «ms-appdata:///temporary/» instead. You can learn more about using app URIs in How to load file resources.

In addition, and unlike other locations, you can also access files in your app data locations by using some Win32 and COM for UWP apps and some C/C++ Standard Library functions from Visual Studio.

You can’t access the local, roaming, or temporary folders through the file picker.

Removable devices

Additionally, your app can access some of the files on connected devices by default. This is an option if your app uses the AutoPlay extension to launch automatically when users connect a device, like a camera or USB thumb drive, to their system. The files your app can access are limited to specific file types that are specified via File Type Association declarations in your app manifest.

Of course, you can also gain access to files and folders on a removable device by calling the file picker (using FileOpenPicker and FolderPicker) and letting the user pick files and folders for your app to access. Learn how to use the file picker in Open files and folders with a picker.

For more info about accessing an SD card or other removable devices, see Access the SD card.

Locations that UWP apps can access

User’s Downloads folder

The folder where downloaded files are saved by default.

By default, your app can only access files and folders in the user’s Downloads folder that your app created. However, you can gain access to files and folders in the user’s Downloads folder by calling a file picker (FileOpenPicker or FolderPicker) so that users can navigate and pick files or folders for your app to access.

You can create a file in the user’s Downloads folder like this:

DownloadsFolder.CreateFileAsync is overloaded so that you can specify what the system should do if there is already an existing file in the Downloads folder that has the same name. When these methods complete, they return a StorageFile that represents the file that was created. This file is called newFile in the example.

You can create a subfolder in the user’s Downloads folder like this:

DownloadsFolder.CreateFolderAsync is overloaded so that you can specify what the system should do if there is already an existing subfolder in the Downloads folder that has the same name. When these methods complete, they return a StorageFolder that represents the subfolder that was created. This file is called newFolder in the example.

Accessing additional locations

In addition to the default locations, an app can access additional files and folders by declaring capabilities in the app manifest or by calling a file picker to let the user pick files and folders for the app to access.

Apps that declare the AppExecutionAlias extension have file-system permissions from the directory that they are launched from in the console window, and downwards.

Retaining access to files and folders

When your app retrieves a file or folder via a picker, a file activation, a drag-and-drop operation, etc. it only has access to that file or folder until the app is terminated. If you would like to automatically access the file or folder in the future, you can add it to the FutureAccessList so that your app can readily access that item in the future. You can also use the MostRecentlyUsedList to easily manage a list of recently-used files.

Capabilities for accessing other locations

The following table lists additional locations that you can access by declaring one or more capabilities and using the associated Windows.Storage API.

Location	Capability	Windows.Storage API
All files that the user has access to. For example: documents, pictures, photos, downloads, desktop, OneDrive, etc.	broadFileSystemAccess This is a restricted capability. Access is configurable in Settings > Privacy > File system. Because users can grant or deny the permission any time in Settings, you should ensure that your app is resilient to those changes. If you find that your app does not have access, you may choose to prompt the user to change the setting by providing a link to the Windows 10 file system access and privacy article. Note that the user must close the app, toggle the setting, and restart the app. If they toggle the setting while the app is running, the platform will suspend your app so that you can save the state, then forcibly terminate the app in order to apply the new setting. In the April 2018 update, the default for the permission is On. In the October 2018 update, the default is Off. If you submit an app to the Store that declares this capability, you will need to supply additional descriptions of why your app needs this capability, and how it intends to use it. This capability works for APIs in the Windows.Storage namespace. See the Example section at the end of this article for an example of how to enable this capability in your app. Note: This capability is not supported on Xbox.	n/a
Documents	documentsLibrary Note: You must add File Type Associations to your app manifest that declare specific file types that your app can access in this location. Use this capability if your app: — Facilitates cross-platform offline access to specific OneDrive content using valid OneDrive URLs or Resource IDs — Saves open files to the user’s OneDrive automatically while offline	KnownFolders.DocumentsLibrary
Music	musicLibrary Also see Files and folders in the Music, Pictures, and Videos libraries.	KnownFolders.MusicLibrary
Pictures	picturesLibrary Also see Files and folders in the Music, Pictures, and Videos libraries.	KnownFolders.PicturesLibrary
Videos	videosLibrary Also see Files and folders in the Music, Pictures, and Videos libraries.	KnownFolders.VideosLibrary
Removable devices	removableStorage Note You must add File Type Associations to your app manifest that declare specific file types that your app can access in this location. Also see Access the SD card.	KnownFolders.RemovableDevices
Homegroup libraries	At least one of the following capabilities is needed. — musicLibrary — picturesLibrary — videosLibrary	KnownFolders.HomeGroup
Media server devices (DLNA)	At least one of the following capabilities is needed. — musicLibrary — picturesLibrary — videosLibrary	KnownFolders.MediaServerDevices
Universal Naming Convention (UNC) folders	A combination of the following capabilities is needed. The home and work networks capability: — privateNetworkClientServer And at least one internet and public networks capability: — internetClient — internetClientServer And, if applicable, the domain credentials capability: — enterpriseAuthentication Note: You must add File Type Associations to your app manifest that declare specific file types that your app can access in this location.	Retrieve a folder using: StorageFolder.GetFolderFromPathAsync Retrieve a file using: StorageFile.GetFileFromPathAsync

Example

This example adds the restricted broadFileSystemAccess capability. In addition to specifying the capability, the rescap namespace must be added, and is also added to IgnorableNamespaces .

For a complete list of app capabilities, see App capability declarations.

How permissions are handled when you copy and move files and folders

This article describes how Windows Explorer handles file and folder permissions in different situations.

Original product version: В Windows 10 — all editions, Windows Server 2012 R2
Original KB number: В 310316

Summary

In Microsoft Windows 2000, in Windows Server 2003, and in Windows XP, you have the option of using either the FAT32 file system or the NTFS file system. When you use NTFS, you can grant permissions to your folders and files to control access to those objects. When you copy or move a file or folder on an NTFS volume, how Windows Explorer handles the permissions on the object varies, depending on whether the object is copied or moved within the same NTFS volume or to a different volume.

More information

By default, an object inherits permissions from its parent object, either at the time of creation or when it is copied or moved to its parent folder. The only exception to this rule occurs when you move an object to a different folder on the same volume. In this case, the original permissions are retained.

Additionally, note the following rules:

The Everyone group is granted Allow Full Control permissions to the root of each NTFS drive.

Deny permissions always take precedence over Allow permissions.

Explicit permissions take precedence over inherited permissions.

If NTFS permissions conflict, for example, if group and user permissions are contradictory, the most liberal permissions take precedence.

Permissions are cumulative.

To preserve permissions when files and folders are copied or moved, use the Xcopy.exe utility with the /O or the /X switch.

The object’s original permissions will be added to inheritable permissions in the new location.

To add an object’s original permissions to inheritable permissions when you copy or move an object, use the Xcopy.exe utility with the -O and -X switches.

To preserve existing permissions without adding inheritable permissions from the parent folder, use the Robocopy.exe utility, which is available in the Windows 2000 Resource Kit.

You can modify how Windows Explorer handles permissions when objects are copied or moved to another NTFS volume. When you copy or move an object to another volume, the object inherits the permissions of its new folder. However, if you want to modify this behavior to preserve the original permissions, modify the registry as follows.

This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, see How to back up and restore the registry in Windows.

Click Start, click Run, type regedit in the Open box, and then press ENTER.

Locate and then click the registry key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer .

On the Edit menu, click Add Value, and then add the following registry value:

• Value name: ForceCopyAclwithFile
• Data type: DWORD
• Value data: 1

Exit Registry Editor.

You can modify how Windows Explorer handles permissions when objects are moved in the same NTFS volume. As mentioned, when an object is moved within the same volume, the object preserves its permissions by default. However, if you want to modify this behavior so that the object inherits the permissions from the parent folder, modify the registry as follows:

Click Start, click Run, type regedit, and then press ENTER.

Locate and then click the registry subkey: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer .

On the Edit menu, click Add Value, and then add the following registry value:

• Value name: MoveSecurityAttributes
• Data type: DWORD
• Value data: 0

Exit Registry Editor.

Make sure that the user account that is used to move the object has the Change Permissions permission set. If the permission is not set, grant the Change Permissions permission to the user account.

The MoveSecurityAttributes registry value only applies to Windows XP and to Windows Server 2003. The value does not affect Windows 2000.