Been trying to do it all night without getting anywhere. Do they usually sort themselves out or should I just delete it?

What device is it on? I have just ended up copying the file and either doing the manual upload, mailing the file to the upload mail address or raising a support ticket.

One of the 3 normally works (in that order)

Have you tried downloading the file to your PC and then uploading it to Strava.
Should make no difference but has for me a couple of times.

It sometimes goes into a loop with me where it won’t synch, then when you press record for your next ride, it will ask if you want to upload the previous data, which will work.

Bad file. Couldn’t upload, export or delete it. Had to un install Strava from the phone to stop it trying (and failing) to sync.

Bum.