This feature is useful to find changes made to the registry. Registry First Aid can create snapshots of the registry, compare them, create undo and redo files. The amount of snapshots is limited only by free space on your disk.
Using the Browse button you can change folder where snapshots are stored.
The Create Snapshot button takes the current state of the registry and saves it to selected folder. To find changes you need two snapshots to compare. A recent snapshot should be selected from the left list and a previous snapshot from the right list.
The button Compare is enabled only if you selected two snapshots to compare.
The Delete Snapshot button deletes selected snapshot file and is available only if you selected one snapshot at the left list.
After you click the Compare button, Registry First Aid loads snapshots and compares them. If any changes are detected, it shows changes in the treeview.
There are two modes for the tree view: full tree and plain tree.
In the full tree all modified registry keys are shown as they appear in registry editor (regedit.exe) - with all its parent keys. This view helps to understand the structure of changed keys.
In the plain view the tree contains only modified registry keys - no parent keys. All items are grouped by root key (HKEY_LOCAL_MACHINE or HKEY_USERS).
Note that the Create Redo File (.reg) for Selected Branch and Create Undo File (.reg) for Selected Branch work with the selected registry key and its subkeys only. To create undo or redo file for all registry changes you need to select the very top item and then right mouse click for menu.