A user reports that it is taking a long time to open files from the server. Which of the following tools should a technician use FIRST to troubleshoot this issue on the server?

"System Monitor" is an older name for Performance Monitor or a general term; in modern Windows, Performance Monitor is the specific tool.

Performance Monitor (Perfmon) is designed to collect and view real-time performance data for hardware and software resources on a local or remote computer. By monitoring disk I/O, network throughput, CPU usage, and memory, a technician can identify bottlenecks contributing to slow file access from the server.

Disk Defragmenter reorganizes fragmented files on a hard drive to improve access speed, but it's a remediation tool, not a diagnostic tool for first identifying the cause of the slowness.

Disk Cleanup frees up disk space by removing unnecessary files, which helps with low disk space issues but does not directly diagnose performance bottlenecks related to slow file access.