How can you prevent users from running the same flow multiple times simultaneously?

Using a Lock element in the flow is an effective way to prevent users from running the same flow multiple times simultaneously. The Lock element ensures that when one instance of a flow is being executed, any subsequent attempts to run that same flow are paused until the first execution completes. This mechanism effectively manages concurrency and prevents the race conditions that can occur when multiple instances attempt to modify shared data or resources at the same time.

When you incorporate the Lock element, you define a unique key or identifier for the lock, which allows Salesforce to track the status of each flow execution. If another user attempts to initiate the flow while it is already locked, they will receive a message indicating that the flow is currently in use.

The other methods for preventing simultaneous execution may not effectively manage concurrent runs. Setting flow concurrency to zero or employing a decision element to check previous runs may not provide the real-time locking and management that the Lock element does. Additionally, stating that it's not possible for Salesforce flows to run independently does not recognize the available tools like the Lock element that can control flow execution. Thus, utilizing the Lock element is the most direct and reliable method for managing flow execution in Salesforce.