Box Sync 4.0 provides detailed user notifications if there an issue syncing a file or folder.
You can only sync new uploads of Mac packages. The Mac package support provided by Box allows collaborators to download packages correctly. If you used Box Sync to sync any package prior to the release of the Mac package support feature, that package will no longer sync automatically.
Follow this sequence to workaround this problem:
Quit Box Sync.
Verify the latest version of the package (Box web application or your local Box Sync directory).
Save a backup of your package to a local directory outside of your Box Sync folder.
Delete the package from the Box web application and your local Box Sync folder locations.
Start Box Sync and wait until your files are synced.
Move the backup of your package (Step 2) back into your Box Sync folder