What is the MOST likely reason for a server shutting down minutes after the cleaning crew starts their shift?

The most likely reason for a server shutting down minutes after the cleaning crew starts their shift is a power surge that may have occurred as a result of their activities. Cleaning crews often use equipment such as vacuum cleaners or other electrical tools that can draw significant power or create electrical noise on circuits. If these devices are not properly managed, they could cause fluctuations in power levels, leading to a sudden increase (or surge) that might disrupt the server's power supply. Servers are sensitive to such power changes, and a power surge could result in an immediate shutdown to protect the internal components from damage.

Other conditions like a hard disk failure, CPU overheating, or memory module failure are less likely to directly correlate with the timing of the cleaning crew's activities. While these failures could indeed cause shutdowns, they typically do not have an immediate link to external influences like those created by a cleaning crew. Thus, the timing and context strongly indicate that a power surge is the most plausible reason for the server's shutdown during this specific period.