Occasionally, you may receive an error, relating to a specific document, that could not be synchronized with the network share. In a majority of cases, the document in question is not synchronized because it's currently "Busy".  You should be able to ignore the error, as it will sync up once you've saved, and closed the document.

In other cases, there may be a document mismatch error, stating that there are two different versions of a document (one on your local machine, and one on the network share).  It gives you several choices (keep one, keep the other, or keep both).  Keep both is the safest in most cases.  Commonly, I choose to retain the one that has the most current "Last modified date" provided by filesync.