It is important to remember that the Windows Registry is a type of database. The last step after the System Restore process involves copying the database from the backup and placing it alongside the remaining files. Upon booting a PC, the system would automatically use the registry. However, corrupted files in the registry or System Restore could be one of the causes of the error. System Restore depends on multiple components to function in the desired manner. The components include system files, Windows Appdata folder, Windows Registry, and many others. If any one of the components fails, then the System Restore process would fail.