A few days ago I bought a laptop and needed sync library of music between it and the desktop computer, so that have the same music library on both computers at all times. There are many services that do this but through the internet, something that seems unnecessary to me if what we want is to synchronize two computers through the local network.
Sailing I found Always Sync, an excellent application to synchronize files between two computers, offering different storage or transfer media. With this little program we can synchronize folders, either on the same computer or with another one. The media it supports range from USB sticks, folders on the same computer, FTP servers, folders located on the local network, Amazon S3, OffsiteBox.com, MS ActiveSync, etc.
I explain more or less the interface of the program, but it is very simple. On the left side we have one of the directories to synchronize, on the right side the other directory, on both sides we have to choose the type of directory or storage medium in question, such as a Windows folder, a folder on the network, etc. Then we have to choose the synchronization direction and that's it.
It is recommended that before synchronizing, give the Analyze button, to see what changes will be made, and if these are very significant, I recommend saving the work as a project, so you can continue the synchronization at any time. When the analysis does not cause any problems, we can proceed with the synchronization itself, which will take time depending on the amount of information and the medium in which it is stored.
Allways Sync is a free program for personal use, it is also very simple to use since it is available in multiple languages. They can download it free from the official site.