CC is failing to sync SOME files, not others

A small number of files I have sent to CC syncing service fail to sync. I have checked all the troubleshooting tips (no special characters in file name, etc.) and none of them apply. The files are .ai files and are big but not super huge: ~ 380 MB ea.

The file names of the ones that won't sync are 006.ai, 007.ai, and 009.ai.  However, other files in the series (made the same way, at the same time, and are about the same size) called 001.ai, 002, 003, 004, etc. all sync fine.

I have tried renaming the failing files before resaving (e.g. 009x.ai ) and they still fail. I have tried opening the original file on my desktop and doing 'save a copy' directly to CC. Still fails.

The consistent error message is "Some files failed to sync". The tantalizing "learn more" link just leads to the disappointingly uninformative message,"unable to sync 007.ai".

I have been trying for days - at first thinking maybe a spotty internet connection was the problem. But it fails whether syncing from home or work, or any day of the week.

I have also noted a message on the Adobe troubleshooting page that for large files, the actual sync doesn't happen until the whole file is copied, and until then the file is flagged as a 'fail'. Well, I've waited hours, and the flag never goes away. (And BTW, if it's true that a still-syncing file might be flagged as a fail and giving a message in past tense ("some files failED to sync") is dumb UX design and should be fixed.)

Running Mac OSX 10.8.5

Am getting really frustrated here. Whatver value CC syncing offers my life and workflow has been erased by the time I have wasted troubleshooting this problem.