files-community/Files · error · NotSupportedException

Specified method is not supported.

Error message

Specified method is not supported.

What it means

ZipStorageFolder.ToStorageFolderAsync throws NotSupportedException. ToStorageFolderAsync on BaseStorageFolder is meant to project the custom storage folder into a real Windows.Storage.StorageFolder. A zip-backed folder has no equivalent OS StorageFolder (the archive is a file, not a real directory), so the conversion cannot be performed and is declared unsupported.

Source

Thrown at src/Files.App/Utils/Storage/StorageItems/ZipStorageFolder.cs:174

			};
			var ext = IO.Path.GetExtension(filePath)?.ToLowerInvariant();
			return await defaultAppDict.GetAsync(ext ?? "", queryFileAssoc);
		}

		public static IAsyncOperation<BaseStorageFolder> FromPathAsync(string path)
		{
			var containerPath = GetContainerPath(path);
			if (containerPath is not null && CheckAccess(containerPath))
			{
				return Task.FromResult((BaseStorageFolder)new ZipStorageFolder(path, containerPath)).AsAsyncOperation();
			}
			return Task.FromResult<BaseStorageFolder>(null).AsAsyncOperation();
		}

		public static IAsyncOperation<BaseStorageFolder> FromStorageFileAsync(BaseStorageFile file)
			=> AsyncInfo.Run<BaseStorageFolder>(async (cancellationToken) => await CheckAccess(file) ? new ZipStorageFolder(file) : null);

		public override IAsyncOperation<StorageFolder> ToStorageFolderAsync() => throw new NotSupportedException();

		public override bool IsEqual(IStorageItem item) => item?.Path == Path;
		public override bool IsOfType(StorageItemTypes type) => type == StorageItemTypes.Folder;

		public override IAsyncOperation<IndexedState> GetIndexedStateAsync() => Task.FromResult(IndexedState.NotIndexed).AsAsyncOperation();

		public override IAsyncOperation<BaseStorageFolder> GetParentAsync() => throw new NotSupportedException();

		private async Task<BaseBasicProperties> GetBasicProperties()
		{
			using SevenZipExtractor zipFile = await OpenZipFileAsync();
			if (zipFile is null || zipFile.ArchiveFileData is null)
			{
				return new BaseBasicProperties();
			}
			//zipFile.IsStreamOwner = true;
			var entry = zipFile.GetArchiveFileData(containerPath).FirstOrDefault(x => System.IO.Path.Combine(containerPath, x.FileName) == Path);
			return entry.FileName is null

View on GitHub (pinned to 68c68a58d4)

Solutions

1. Do not call ToStorageFolderAsync on a ZipStorageFolder; keep operating through BaseStorageFolder.
2. If a native StorageFolder is required, extract the archive to a real temp directory and use StorageFolder.GetFolderFromPathAsync on that.
3. Type-check and reject the conversion for zip-backed folders.

Example fix

// before
var native = await zipFolder.ToStorageFolderAsync(); // throws

// after
// operate via BaseStorageFolder APIs only
var items = await zipFolder.GetItemsAsync();

bool CanConvertToNative(BaseStorageFolder f) => f is not ZipStorageFolder;

static bool IsZipBacked(BaseStorageFolder f) => f is ZipStorageFolder;

try { return await f.ToStorageFolderAsync(); }
catch (NotSupportedException) { /* operate via BaseStorageFolder APIs */ }

When it happens

Trigger: Calling ToStorageFolderAsync() on a ZipStorageFolder (root or inner entry folder). Typical source: a component that requires a native StorageFolder (e.g. a picker or a shell-bound API) and tries to convert whatever BaseStorageFolder it received.

Common situations: Third-party or framework code that calls AsStorageFolder()/ToStorageFolderAsync() to obtain a native StorageFolder for a folder broker that is actually a zip interior.

Related errors

• Specified method is not supported.
• Can't open zip file as RW
• Moving to recycle bin is not supported.
• Moving to recycle bin is not supported.
• The method or operation is not implemented.

AI-assisted analysis of files-community/Files@68c68a58d4 (2026-08-13). Data as JSON: /api/errors/d0fdb9a7644fe13c. Report an issue: GitHub.