How To Delete .FIT File From Previous Owner

The best thing to do, is to perform a full reset, deleting all settings and data. Once that's done, configure the watch for you.

The other option is to connect the watch to a computer. Delete the contents of the Activity folder. 

Thanks.  I actually did the reset once, but may have done it out of order, i.e. after I had already sync'd the device to my computer, which I assume transferred the old activity to my computer.  I really would prefer not to reset again.  Can you tell me where/hot to find the Activity folder, and can I just delete that one activity (I would like to keep my own).

There is an option to do a reset that includes deleting data and settings. I would still recommend you do that to ensure all the previous owner's data and settings are removed Settings, System, Reset. From what you are saying it would appear that you might have done something other than clearing the data and settings.

Files are saved in date order so you should be able to work out which are yours. 

Thank you so much philipshambrook!  I found the suspect file (it was actually located in SCRCRDS), and deleted it.  But now, when I try to log into Garmin Express, it still throws the same error (User not authorized to update file), but now, in the dialogue box where the file used to be, there is nothing, LOL!!  When I click "Try Again", 100% of the time it tells me "We are having difficulty connecting to your Garmin Connect Account.  Please re-enter your credentials".  So, I log back in, and the whole cycle repeats.  "User not authorized to update file", and "We are having trouble connecting to your Garmin Connect Account, Please re-enter your credentials".

I have to login at LEAST 4 times, and then somehow it seems to clear.  Then, the next time I plug in my watch, that whole cycle repeats. VERY frustrating.  That Garmin Express interface is just clunky as hell. Anyone else getting those same errors?  Not authorized to update file, and having to re-enter credentials over and over again?

In your specific case it's more likely to be because you've inherited something from the previous owner. Do you know if the previous owner removed the watch from his account? If you're reluctant to do a full reset clearing all data and settings (which I think is the best thing to do) go back to Garmin Express and remove the watch from there. There's also an option there to remove Update History that might help too. Perhaps even completely delete and reinstall Garmin Express before adding the watch again. 

I lost the source of the information, but vaguely recall something about SCRCRDS, that it has something to do with golfing, and that you have to specifically set up your Connect account correctly for golfing. Maybe that affects things.

But in an any case, doing a full reset, deleting everything, removing the device from your account and starting over, is probably the best option here.

I have lots of experience with using pre-owned Fenix watches, everything tends to get difficult if you don't do a full reset before starting to use it. It can't hurt to call to local Garmin Support to check if the Fenix is still registered in the previous owners account, they can resolve that for you.

Al comprarlo te dieron la boleta de compra, si no la recibiste lo mas seguro que sea robado, al ser reportado como robado a su dueño original, se bloquea, da diferentes problemas de conexión, incluso puedes ser acusado de receptación, se esta tomando muy en serio la seguridad y afiliación de usuarios que ya tienen un historial de compras de sus dispisitivos.