Did a ride with my 1040 today and at the end it seemed to save it only to find later it did not show up on the unit or sync it.
I went into the unit in HD mode and looked at the Activities directory, the .Fit file was there. I was able to upload it to Strava but couldn't get the unit or Garmin Connect Web App to load it. When Connect tried to load, it said contact support and here I am. :) FW is 21.16.
Tried to upload the file here but didn't like the extension.