Favor is still as it was mate, no rebuild needed.
As for you update issue, i had a very similar thing happen when i went to update the latest patch, except i would stop at 8%.
The it would error and pause.
I kept resetting the Impulse data and nothing eventuated.
I'm not totally sure what in the end fixed my issue, i cycled modem and restarted PC then launched Impulse and started the update again and walked away. When i cam back it was done.
Sorry that i can't offer advice, but if it's the same thing that happened to me, it might just need perseverance.....unfortunatley.