sduck wrote:
Sunfalls and myself (we're in touch via another forum) have discovered that both of us are using macbook pros running OS X 10.11 – you might want to consider testing with this combo, see if the installer might be the problem. Significant changes were made in 10.11 in how USB is handled.
I was testing myself yesterday on a MacBook Pro running OS X 10.11, and I didn't encounter any updating problems. It could be that the problem is still related to MacBook Pros running OS X 10.11, but it isn't the case that updating with that combination is going to cause this sort of error every time.
