OneDrive for Business has a number of limitations on what it is capable of syncing on both Windows or OSX. A full list is available at Microsoft: https://support.microsoft.com/en-us/kb/3125202
The following characters in file names aren't supported when you sync OneDrive for Business:
# (number sign)
% (percent)
< (less than)
> (greater than)
: (colon)
" (double quote)
| (pipe)
? (question mark)
* (asterisk)
Any file that’s currently opened by an application (for example, an Excel .xlsx file) can't be synced by OneDrive for Business. To sync the file, close any application where the file is currently being used, and then sync the file.
There is a 10-gigabyte (GB) file size limit for each file that is uploaded to the OneDrive for Business library.
OneNote Notebooks can only be synced via a free consumer Microsoft account
Because OneNote notebooks have their own sync mechanism, they aren't synced by the OneDrive for Business sync client. Instead, you should save your OneNote files through OneNote or the web to OneDrive. OneDrive will create a stub file in your sync folder, depending where you saved the OneNote file
SharePoint Online has a limit of 30 million documents per library. There are other limits on viewing a document library by using the web that may limit how you structure your files in OneDrive.
The current version of the next-generation sync client doesn’t yet have the deep Office integration you’ve come to expect. We are working with the Office team to bring this integration back as quickly as possible. In the meantime, if you typically open synced files from Windows Explorer, you will be opening the local file instead of the file that’s stored in SharePoint Online. There are several limitations: