Why is it crucial to avoid turning on a computer during an investigation?

Avoiding turning on a computer during an investigation is essential primarily because it carries a significant risk of tampering with evidence. When a computer is powered on, its operating system and applications may modify or overwrite existing data, delete files, or change timestamps associated with files and system usage. Such alterations can hinder the ability to accurately reconstruct events or recover crucial information, ultimately jeopardizing the integrity of the investigation.

Preserving the original state of the device is fundamental to forensic practices, as it ensures that any digital evidence collected can be trusted in a legal context. Investigators typically employ methods to create exact copies of the storage media in a write-blocked manner to prevent any changes to the original data while still allowing analysis to occur safely.

The concern regarding data loss is important but secondary when compared to the potential for evidence tampering, as tampering could undermine the entire investigation. Focus on the monitor, and conducting diagnostics doesn't adequately cover the primary risk associated with booting up a computer during an evidence recovery operation.