Thanks @iMic
I guess the “good” part is - it’s not crippling the system - it works fine once it does its restart, and when it does happen, unlike in the link above, it seems to restart fairly quickly - even the progress bar for the restart process appears to start at the half way mark.
At least your suggestions indicate it’s not necessarily a hardware issue - appears to be more software related.
Will have to have a play around…
My MacBook Pro does the same thing!! It’s annoying. I have a White 2010 MacBook that doesn’t and a 2008 White MacBook that doesn’t.
Mm.
Not sure if it’s the sleep / restart cause - but just ran the internal hardware test (‘d’ key during startup).
VDH002 - Storage device issue
I noticed earlier, 1 screw doesn’t sit flush on the rear panel - which really doesn’t tell me buckets of information, other than - someone’s been inside before - possibly to instal a new / larger SSD?
I’ll open her up later today and look for any obvious… anythings…
Is there any SSD tests I could perform based on the above error code? Is this error a definitive - you have to replace - or could it just need reseating or ? (Though presumably in that case it wouldn’t work at all…)
It’s probably worth noting - when it restarts, it hasn’t remembered anything… Firefox for example has its “Oops something went wrong” message, and offers to restart the windows. It’s not like it’s taken a snapshot… So the hibernate function isn’t taking place.
Mmm.
So, hibernate mode was set to 3 - Safe sleep - not hibernate.
I changed it to 0.
But, the machine still crashes/reboots if left alone for x hours.
The SSD is not genuine - shows up as “Feather M13 256MB”, under NMVE - not “storage” under the system profile.
My pentalobe screwdriver just arrived, so I’ll pop it open shortly to take a look…
Sleep issues with non-original SSDs in those models are well known. See here: Upgrading 2013/2014 Macbook Pro SSD to M.2 NVMe | MacRumors Forums
Just disable hibernation by typing “sudo pmset -a hibernatemode 0 standby 0 autopoweroff 0” in the terminal and if should be ok. 
Yeah @jaysee - so I’m learning!
I set the hibernate mode to “0”, but it is still crashing after a few hours on sleep. I’ve just checked and the bootrom is 110.0.0.0.0; latest version for this model is 117.0.0.0.0. Not real convinced that is the issue, but I think I’ll try an OS re-instal and see if that helps.
I needed a laptop for work yesterday, so proudly took it in, and whilst everyone else was lugging in clunky windows boxes, that all needed to be plugged in to power, I happily sat there with my cute lil Air running off the battery. Easily lasted the distance (only 5 or so hours, light web use during a training course - but still had 65% battery remaining at the end).
Opened the case up. The SSD is a “Fledging” (Take Flight!). Dust free. No other obvious issues. Stripped 1 screw putting the case back on…