Adding an entry to the system startup items without asking the user for permission or adding a system icon to the list of devices is another. Monitoring those Registry and file changes can be helpful in analysing why something happened and where it’s source is located.

What Changed is a portable system application that can take system snapshots and compare those system snapshots with a system state at a later time. This can be highly useful during software installation. A system snapshot would be created before the installation and that snapshot could be compared to the state of the system after the installation.

The computer’s file system and the parts of the Registry that should be scanned for the system snapshot can be selected in the program interface. Taking the Registry and system snapshot takes a while depending on the size of the hard drive and the amount of files stored on it.

The same main interface contains the Compare button which compares a previously saved system snapshot with the current state. The program basically scans the system a second time and compares the first and second snapshot to discover differences.

The changes are saved in a snapshot file in the same directory as the application. It’s a simply text file that points to Registry keys and files that have been changed or added.