The other day, though, when attempting to sync the data post-run, iTunes complained about not being able to validate my data. The data was not uploaded and would not re-sync on reconnecting the Nano. It happened again the day after, losing me a total of eight kilometers.
Seems this was a widespread issue.
The problem didn't occur again after today's run. Later, I followed these instructions for re-uploading run data, though I used the terminal instead. The runs now synced fine, without causing the validation error.
The name of your iPod, the identifier of your Nike+ and the filename for the run will vary from these values. Tab completion is your friend.
Connect your iPod and allow it to mount.
Go to the
Move the file to the
mv 2006-12-06\ 17\;40\;02.xml ../latest/
Navigate out of the Nano to allow ejecting it:
Eject the Nano. Plug it back in. It should sync the run again.
Re-syncing a run that was already successfully synced does not seem to cause any problems – it is not duplicated, only flagged as new (but with its actual date maintained). Re-syncing older runs, after successfully having synced newer runs, didn't cause any issues, either.
It seems Apple Discussions (where I found the thread I based this on) disallows search engine indexing, so hopefully this post will add googleability to the issue and solution.