Etrex 20 missing recorded track

[Feanor]

had a good rumage on the disk and there are no .tmp files

so the eTrex 20 seems to have totally failed for no apparent reason

Hmm, well, welcome to the wonderful world of Garmin.

I bought an Edge 810 whilst my Edge 800 was Waiting-on-Parts.
It's a pile of poo.

The old Edge 800 crashed around 400k, but this was a known issue, and re-setting it around 300k worked fine. You had to splice the tracks, but that was not a problem.

The edge 810 crashes randomly: I've had it crash at 15k, 70k, 230k. Yet it's managed 400k without crashing.
Much more unpredictable.
When it crashes, it leaves a .fit file that is not correctly closed-out, and will not upload anywhere without repair, but is otherwise fine.
The activity will also not show up on the device, on account of being corrupt. But the file is still there.
Tools like FitFileRepairTool will read it OK.

On my recent 600, I had 2 crashes. But I was able to re-construct the track using the Fit File Repair Tool.
Had I lost a 600 on account of the Pile of Poo, I would have used Stronger Language.

Now that my old 800 is fixed, I will use it for Audax events in preference to the 810.

[vorsprung]

okay it's lost another file which was a recording of a ride.  Bit of a pity as I'd done 100km by a slightly different route and wanted to see if I scored 2000 metres ascent.  The only way to see this is to download the gpx and put it in a gpx editor

The device had not got wet, the file size wasn't over 10000 points so why it freaked out I am not too sure

I tried really hard to get it back using various IT voodoo ( although the Garmin Etrex I have has a vfat filesystem so voodoo is somewhat limited)
Best I could do was the first 4096 bytes of the file but it should be 334625 bytes

The file has gone forever but maybe a factory reset will help matters with the etrex20 loosing tracks, will try that at some point soon.