I did split my rout using BaseCamp for Mac. Exported new rout as GPX. Now I could not upload this GPX file in GC. The error message is "Some activities could not be created".
I've had that problem too. What I found to be the problem is that BaseCamp puts a 3-byte Byte Order Code (BOC) in front of the gpx data and Connect doesn't recognize it. I reported this to Garmin months ago but they don't seem to care that one piece of their software can't talk to the other.
If you're a computer geek, here's what you do to fix the problem. Download a "hex editor" like http://xvi32.en.softonic.com/. Open the gpx file created by BaseCamp. If the first byte is not "3C" it means the BOC is there (always is when I edit a gpx with BascCamp) and must be deleted. Select the byte right before 3C and do a Edit|Delete to cursor. Save the file. It will now upload to Connect.
Well, it looks like Connect has been fixed to recognize gpx files exported from BaseCamp.
I imported a file for a recent hike during which the batteries had to be replaced. When this happens the gpx file has two separate tracks. So I Imported the file into BC, joined the two tracks, and exported to a new gpx file. I opened the file with the XVI32 hex editor and saw it had the usual three-byte Byte Order Mark (BOM) at the beginning. In the past, Connect refused to upload such a file, but today it did. Hurray!
