This is going to be short and sweet.
There are numerous issues with the sync client for OneDrive for Business but NOT with the sync client for OneDrive (the personal OneDrive that is not related to O365). There has been a large amount of chatter within MVP circles about the problems and the general consensus is that you should NOT use the sync client at this point.
So, at the risk of having my MVP badge and secret decoder ring being taken away, I’m going to go out on a limb and recommend, strongly, that you DO NOT USE the ODFB sync client until further notice! Microsoft is painfully aware of the issue (Lord knows, the MVP community has been raining hellfire and damnation down on the appropriate parties inside Microsoft about the issues) and work is ongoing to fix the problem but as of today (October 3, 2014) the sync client should be considered as dangerously unreliable.
OneDrive (NOT ODFB) does NOT have any issues so if you really, really need the sync capability then OneDrive (NOT ODFB) is the way to go for now.
Now I have to go see if the secret messages still decode using my ring ….