During what project management process does the project team begin identifying risks?

The Initiating process group is focused on authorizing the project and defining it at a high level - it does not include formal risk identification processes.

The Identify Risks process is part of the Planning process group in PMBOK's Project Risk Management knowledge area, and this is when the project team first conducts a structured effort to identify potential risks and document their characteristics. Beginning risk identification during planning allows the team to incorporate risk responses into the project management plan before execution begins. Risk identification is iterative and continues throughout the project, but the formal start is in the Planning process group.

Executing is too late to begin the initial identification of risks, as risk responses should already be planned before work commences.

Monitoring and Controlling involves monitoring identified risks and identifying new risks as the project progresses, but the initial formal identification starts in Planning.