I've just had my Forerunner 405CX for two days and am slowly figuring this all out. I accidentally hit the start button after I returned home from a run and was trying to come out of power save mode so I could upload with the ANT agent. Since I didn't delete the new lap I had just created, and wiped the data off the device after it uploaded, I tried to edit the TCX file I had exported out of Garmin Connect so I could remove the errant lap (which was just a second long and far away from the location of my run).
I just deleted the lap (and the 0.01 mile lap before it) in the tree using XML Notepad 2007. However, Garmin Connect won't let me upload it. There must be something wrong with the file. Can anyone take a look and see if there are problems with the file?