Hopefully by now you know that when it comes to SharePoint, SharePoint Online and OneDrive for Business there are limitations when it comes to syncing files to your desktop. Most of these are contained in the article:
Interestingly, when it came to filenames there were certain characters, that if in a filename, would prevent that filename from syncing. Generally, these characters were the same for SharePoint Online and SharePoint on premises. However, as someone pointed out to me this is no longer the case.
The above article details how the ‘&’ character is no longer invalid for SharePoint Online but remains so for SharePoint Server 2013. When you read the article you’ll also see that there are beginning to be quite a few differences in what is permitted between SharePoint Online and SharePoint Server 2013. This is clearly an indication that SharePoint Online is being updated much faster than SharePoint Server 2013.
So now you’ll have to check the above article a little more closely to see exactly what is an isn’t permitted for different versions of SharePoint.