A7 II lost Date and Time

[bitsnpieces]

Compared with your other cameras, are you charging them the same way? Via external adapter and not USB? Or via USB?

Sony's method of resetting, just like many other electrical devices, is via taking out the battery. If the battery out for too long, it usually will ask you to set the date again. The duration it takes before it asks you though, I don't know.

But Sony's reset method is taking it out for 1 minute or so, and pushing a button (can't remember) as you put the battery back in. That activates the hard reset. If I remember correctly, that was the process (have to double check)
You mentioned that the other settings aren't affected, so I can't see it being a hard reset, but who knows. Maybe just haven't noticed yet.

And who knows, maybe you may be accidentally pumping one of the buttons every now and again when putting the battery back in.

But yes, it is pretty normal for it to ask for the date and time again, but again, I don't know long it is before it'll ask for a reset.

[antony]

Thank you guys.

Compared with your other cameras, are you charging them the same way? Via external adapter and not USB? Or via USB?

All my Sony E-mount cameras (NEX-7, A7R, A7 II) were charged the same way: use Sony BC-QM1 instead of USB.
I also have one Sony AC Adaptor (AC-PW20) which I use often for studio shooting. I share it with A7R and A7 II. Like A7R, there are times that A7 II is not connected to AC-PW20 nor battery inserted, however the resetting of date/time does not happen in A7R.