Synchronize two folders (SyncToy)

To synchronize two folders in basic terms means to update one or both of the folders so they both contain the same set of folders and files. It is a great way to keep two copies of folders and files without making a new copy each time you need to update it.

SyncToy is an old Microsoft program that will inspect two folders and work out which files need to be added or deleted so both folders contain an identical set of folders and files, which makes it a vital program to use for keeping a backup on an external hard drive up to date (refer to our July 2014 article).

Go to and click the download button for SyncToy. Tick the option that ends in x64 and then click the “Next” button. A confirmation page will display and the download should start automatically. Save the file and then go to your Downloads folder and double click the install file to start the installation.

Once the program has finished installing, press the Windows key on your keyboard and type “Synctoy” to locate the program and click the “SyncToy” program in the search results to open it. The first time SyncToy runs, it may ask you to participate in a customer experience program and we recommend you decline to participate.

The next step is to set up some folder pairs – these are the two folders you want to synchronize, which SyncToy calls the Left and Right folders. Usually the left folder would be the original folder, for example in a backup scenario, the left folder would be a folder on your computer and the right folder would be an external hard drive.

Click the “Create New Folder Pair” button and select the two folders you want to synchronize by clicking the “Browse” button. Keep in mind that you can create as many folder pairs as you wish. The next step is to choose the synchronization type – there are three different types to choose from depending on what you are doing.

For backups, the Echo option is what you should use because only the files on the right folder (your external hard drive) are updated, matching those in the left folder. The Synchronize option copies new files added to either folder to the other, or any files deleted in any of the two folders are deleted in the other.

Click the Next button, enter a name for this folder pair and click the finish button. Now to actually synchronize your files, click on the folder pairs name in the left panel and click the preview button first to see what files will be affected. If the results are as expected, click the run button for that pair to make the actual changes to your folders.