How do I edit an activity if I forget to stop the session?
you can use the online tools here to cut your files to length ... www.fitfiletools
check if you can repair your file with help of FitFileRepairTool
with your consent we can have a look at your file with FitFileRepairTool
zip the fit file and upload here in the forum, or provide a link to it on a cloud storage
happy & safe sporting