Single Folder Not Syncing

Have a folder that has a bunch of content, but none of it is syncing to my pc. The only error I receive is the following: "Sync Failed: File May be in Use" Try again later. 

Nothing is using those files, not opened anywhere else. So all the content is up on box when I look at it using a browser, however It's not syncing to PC.

Any suggestions? 

Thanks.