Part of running a business means dealing with personnel issues. When an employee comes to you with a harassment, discrimination, safety or any other type complaint, be sure to listen and investigate. Conducting workplace investigations is one of the most challenging HR duties, but also one of the most important. Some of the most common mistakes include: not taking the situation seriously, not conducting an investigation at all, failing to write a report, or failing to follow up with those involved. That sets employers up for trouble should that employee end up filing a lawsuit. On the other hand, conducting an investigation in a prompt, thorough, and fair way can be your first line of defense should a situation come back to haunt you.