Cancellation token

[Robert-Capra]

I found out that cancellation token stops the download but the file remains still held in a process forever, to fix this i had to make:
new Task(async () =>
{
await youtube.Videos.DownloadAsync(x,
y,
z);
},cancelToken).Start();
if i do this, the file is locked in process
await youtube.Videos.DownloadAsync(x, y, z, canceltoken);
is anything i did wrong?