Well, after about 1 ½ hours on the phone with a bloke from AppleCare I'm not too sure if I am drilled, bored or countersunk ? But he now has a set of logs and several screen dumps to send on to the Apple engineers and he said that they should be back with more information within 4 working days.
We tried yet another T M backup so he could see what was happening and told me that he had never seen or heard of anything like it before. I showed him, via his 'look at my screen' app and he was surprised that there were so many hits on the problem? Surely Apple MUST know that something is seriously not right?
T M is something that you start, watch for a couple of minutes on the first time and then just let it get on with it? If so then there could well be a huge number of users that could be in for a very nasty shock if they ever have SSD problems or need to recover data.
So the basic outcome of today is that I'm still no wiser at the moment, but it still looks as if it could be a total wipe off and reload depending on if/what the engineers find?
Watch this space, I think? Anyone got any valium they don't need
