If you need to synchronize different directories on your computer, multiple computers, or between your PC and your NAS, then here’s a small software for Windows that you’ll like.
It’s free and it’s called Echosync. This software, which can also run in portable mode, allows you to keep a USB key, an external hard drive, or a NAS always up to date. To do this, you create a Sync profile by specifying the directories, and the copy will only be done in a unidirectional way.
That means the source won’t be modified (read-only). So it’s easy to use and there’s no risk of making mistakes. In addition, Echosync is capable of performing a differential synchronization, meaning it saves only new or modified files, without resynchronizing all the data. It saves time!

Its detection algorithm can also detect renamed or deleted files, which avoids deleting them and then copying them again. Echosync also uses VSS (Volume Shadow Copy) to copy read-only locked files and can handle any type of path even those that are more than 255 characters long or contain symbolic links.
You can also use it in the command line to automate all of this through the Windows Task Scheduler.
It’s a small software that can be very useful, and simple to use, and in addition, it’s super fast and reliable.
If you’re interested, you can download it here (+ Windows Store) or install it via Winget like this:
winget install SylvainRougeaux.Echosync
Have fun!”