StorageFile.DeleteAsync() delete file fail without any exception sometimes.

Question

I develop a test tool to Write a file, then delete it, over and over again.
Using "await StorageFile.DeleteAsync()" to delete file , sometimes, it run successfully without any exception, but the file to be deleted wasn't deleted as expect. Why the API " StorageFile.DeleteAsync" doesn't work?
Thanks.

Answer 1

Hello,
Code is as this:
 private async void SDCardFile(String basename)
            while (true)
                if (this.isStop)
                    return;
                Boolean isWirteSuc = await WriteSDCardFile(fileName, writeText);//writefile
                if (isWirteSuc)
                else
                Boolean isDeleteSuc = await DeleteSDCardFile(fileName);  //deletefile
                if (isDeleteSuc )
                else
 private async Task<bool> DeleteSDCardFile(String filename)
            try
                StorageFolder externalDevices = KnownFolders.RemovableDevices;
                StorageFolder sdCard = (await externalDevices.GetFoldersAsync()).FirstOrDefault();
                StorageFile storageFile = await sdCard.CreateFileAsync(filename, CreationCollisionOption.OpenIfExists);
                await storageFile.DeleteAsync();
                return true;
            catch (Exception ex)
                return false;
I use a timer to stop the test after 12 hours, during this test, most of the file delete success, but some failed, it still return "true"  from "DeleteSDCardFile(String filename)", so there is no exception, but the file is not deleted,
I can find these files on SD card.
Look forward to your answer, thanks for your comments.