None of this information is necessary to use SyncToy. It is provided as a service to advanced users who want to understand more about what SyncToy is doing "behind the scenes."

• SyncToy stores its data in a folder named "SyncToyData" in your "My Documents" folder.
• Folder pair data is stored in the "SyncToyDirPairs.bin" file in the "SyncToyData" folder.
• Other files with a .bin extension in that folder are SyncToy snapshots, which contain data on the files on each side of your folder pairs. SyncToy compares the contents of the snapshot files to the current state of the corresponding folder on your machine to determine if you have renamed or deleted any files.
• You would not ordinarily want to delete any of the snapshot files because they are essential to a number of SyncToy features, including the ability to recognize rename and delete operations. Should you decide to delete a snapshot file, however, you may do so by following these steps:
  1. Select the folder pair whose snapshot you want to delete.
  2. While holding down the shift key, select the Preview button.
  3. The snapshot file will be deleted and a preview of the folder pair will be displayed.
• SyncToy does not allow editing of the left or right folder in a folder pair, or of the folder pair name, because changing any of these items invalidates the stored snapshot and disables -- for the next run at least -- many of SyncToy's most important features.
• SyncToy adds a hidden file named "SyncToyDirectoryId.txt" to each of the top-level folders in all of your folder pairs. This file contains a code that lets SyncToy uniquely identify the folder. This feature is particularly important when you are synchronizing removable media. SyncToy can use the information in this file to tell, for example, one compact flash card from another and will not scramble your files if you swap the cards around. It can tell the difference between "d:\pictures" on one card and "d:\pictures" on a different card. You would not ordinarily want to delete any of these files if you plan to use SyncToy in the future.