Replay Bug where It freezes my whole computer trying to save a replay.

So I've had a couple of games where an outplay has occurred or a funny bug or two.

I've wanted to save them to share with mates, but the game freezes straight away after I hit record and wouldn't fix even after waiting a while. I've got a pretty powerful computer, good internet and have tried many times and it still won't work, anyone got any advice what I could do?

It never used to do this before last year and would save quite easily in the past.