Just my opinion, BlockInput() seems like a sledgehammer to crack a walnut. On a multi-tasking operating system, the user may wish to interact with other applications during that time but won't be able to.

Indeed, but I've tried every other possible way of blocking,removing,ignoring input and nothing has worked.

I'm surprised that sync() didn't work.

I'm surprised that sync() didn't work.

I don't know why that would be surprising. sync() isn't guaranteed to do anything at all on input streams.