UnauthorizedAccessException in CopyAsync

Question

I got a UnauthorizedAccessException in ~20% Copy Files Async

public async static Task DirectoryCopy(string sourceDirName, string destDirName, bool copySubDirs, ProgressBar pb)
    {
        DirectoryInfo dir = new DirectoryInfo(sourceDirName);
        if (!dir.Exists)
        {
            throw new DirectoryNotFoundException("Source directory does not exist or could not be found: " + sourceDirName);
        }

        DirectoryInfo[] dirs = dir.GetDirectories();
        if (!Directory.Exists(destDirName))
        {
            Directory.CreateDirectory(destDirName);
        }
        float files = Directory.GetFiles(sourceDirName, "*.*", SearchOption.AllDirectories).Count();
        float count = 0;

        foreach (string dirPath in Directory.GetDirectories(sourceDirName, "*", SearchOption.AllDirectories))
        {
            Directory.CreateDirectory(dirPath.Replace(sourceDirName, destDirName));
            foreach (string filename in Directory.EnumerateFiles(dirPath))
            {
                using (FileStream SourceStream = File.Open(filename, FileMode.Open))
                {
                    using (FileStream DestinationStream = File.Create(filename.Replace(sourceDirName, destDirName)))
                    {
                        count++;
                        float percentage = count / files * 100;
                        pb.Value = (int)percentage;
                        await SourceStream.CopyToAsync(DestinationStream);
                    }
                }
            }
        }

        foreach (string filename in Directory.EnumerateFiles(sourceDirName))
        {
            using (FileStream SourceStream = File.Open(filename, FileMode.Open))
            {
                using (FileStream DestinationStream = File.Create(destDirName + filename.Substring(filename.LastIndexOf('\\'))))
                {
                    await SourceStream.CopyToAsync(DestinationStream);
                }
            }
        }
    }

And

try
            {
                StatusBar.Text = "Trwa kopiowanie plików...";
                await CopyAsync.DirectoryCopy(game_path, installing_path, true, LowerPB);
            }
            catch (UnauthorizedAccessException)
            {
                Error.ShowError("You don't Have Permission! Run as Administrator!");
                Environment.Exit(0);
            }

Any suggest how i can resolve this problem?I'm trying to fix it for 20 minutes and I do not know what it is. I am trying to run as an administrator and it also does not work.