Partially Corrupt Garmin File

I’ve just uploaded a file to Strava from my Edge 510 that has come up with correct overall time, distance and elevation but has lost most of the data from the file somehow, I had a random switch off towards the end of the ride – I’ve tried opening the original garmin file in a text editor on my mac and there’s a load of data missing (I assume that the data is the positional info taken every second) but the overall is correct so I’m really confused – is there any way to rescue the missing data? I was on a good ride testing some new wheels so am really interested in the lost data.

Cheers,

Si