You have a remote possibility using recovery tools to be able to undelete the fit file. Turn the wtch off, since writing any more data to the watch could overwrite the deleted file. Only turn it on when you're ready to try one of these file recovery scans. For Windows PC I've had luck with Recuva but I've never tried it on a Garmin device. On a Mac, there are tools such as Bitwar.
Sorry I couldn’t respond in time to assist. I deleted a run by accident from the app. I went to “Edit my day”, and at the top it said to “restore deleted cards from today”. I chose that (it disappeared) then i chose Save. The run came back!
You deleted it from the app, not from the watch. Deleting from the watch is a little more difficult to recover from if you haven't yet synced to Garmin Connect.
