Lenovo notebooks cannot allow "System Restore" to permanently retain a restore point. "System Restore" is a basic change tracking tool, not a mirroring tool or a backup tool. Each restore point stores the changes that have occurred in the system since the previous restore point was created, which minimizes the hard disk space it takes up and improves performance, so all restore points are related to each other. Therefore, restoring the system from the current state to a previous state requires the use of all previously established restore points. For example, if the user wants to restore the system from point D to point A, "System Restore" will check the system change logs of points C and B, and if a restore point is a permanent restore point, it will be stored in the permanent restore point. The space for the entire restore point chain created after the restore point would be very large and impractical. "System Restore" also provides a space management function that can be used to clear older restore points to make room for new restore points, thus forming a rolling safety net. By default, restore points older than 90 days are automatically purged.
