Garmin sent me an email admitting that their firmware is broken but did not offer to give me the old version. they are "working on a fix".
WARNING: computer geek info alert :rolleyes:
I was able to fix two corrupted ride files from my Edge 705 using the free program firstobject xml editor (http://www.firstobject.com/dn_editor.htm)
The files are stored in .tcx files a directory called History on the Garmin.
A typical .tcx trackpoint looks like:
<Trackpoint>
<Time>2008-07-05T18:20:01Z</Time>
<Position>
<LatitudeDegrees>47.577279</LatitudeDegrees>
<LongitudeDegrees>-122.139872</LongitudeDegrees>
</Position>
<AltitudeMeters>97.711</AltitudeMeters>
<DistanceMeters>0.384</DistanceMeters>
<HeartRateBpm>
<Value>144</Value>
</HeartRateBpm>
</Trackpoint>
You are looking for <tags> that don't match up to </tags>. When you open the file in firstobject it will give an error at the bottom of the window that lists the offending tag and where it is in the file. It helps if you use the Tools>Align menu option to list the tags in sequential order with line breaks between them. Find the bad spot and delete <tags> until all of the <Trackpoint>...</Trackpoint> sets are complete. Then the file will probably load into Training Center once you save it.
If the problem is missing information in the file header or footer you can copy that part from a good file and edit it to have the correct start date, distance, duration, etc. to make a valid tcx file. That method can also be used to convert an orphan .dat lap file in the History>Laps directory into a valid .tcx file.