Sigh... this is still being a freaking PIA....
If it gets to the point where I have to type my pwd in before I can get back onto my machine, it seems to be fine.
But if it doesn't get to that point & I try to start using my machine again...
The AP will be sitting there in plain site, but the rMPB won't attempt to connect until I manually select it from the menu!
I haven't yet tried ALL the things listed, I definitely won't be doing number 10, even if all the others don't work!
I've since found that even a complete reformat & reinstall doesn't get rid of it completely... >.>
For a long period it definitely worked without issue, but now some sort of hw fault's creeped into the laptop, the AP, or there's more Wifi noise in the area than before.
I doubt it's the AP, as none of my other devices have had the same (or similar) issue, not that I've seen yet anyway.
First I'll rule out interference, I have some tools that'll help me devise a wifi config. that results in the least amt of interference for my AP/clients.
If there's still problems, I'll swap out my current modem/AP/router for a spare modem + AP/router I have.
If there's still problems, well, I think we've exhausted everything & can pretty confidently say my rMBP's Wifi client is sub-par, & must be placed on the service/support merry-go-round.
Still have this issue since I last posted, I've learned to live with it by having BT turned-off all the time.
Only when I need BT do I turn it on...
Sometimes I forget to turn BT off after I've finished using it & the problem comes back, so it's def. some kind of hw issue.
I could've gotten Apple Care to look at it ages ago, but I just can't afford to be machineless for more than 24hrs.
It's really not acceptable for such an expensive machine...
If anyone's observed this issue on other mid-2012 rMBP's & know how to fix or worked-around it, please share.
I hope to have a completely upgraded W/LAN infrastructure by the new yr, so maybe that'll improve the situation.
And I still haven't done everything I said I'd do in my prior post, time permitting I'll get round to that too.