This NIJ Special Report presents test results of SafeBack 2.18, an electronic evidence preservation tool that creates mirror-image backups of computer hard disk drives. It describes the testing environment and 4 anomalies detected among the test cases; documents test results against 22 test assertions (both mandatory and optional); and includes summary log files of 112 test cases. The results provide information necessary for developers to improve tools, users to make informed choices, and the legal community and others to understand the tools' capabilities.