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Only 1 flow should create event, and the rest should be declined

I have a desk booking system using PowerApps. From the app, multiple users can book for desk after selecting the location and time. Once book button is clicked, all the information will be sent to SP list. The flow is triggered when new item is created in the list. At the end of the flow, an event is created inside Outlook to indicate the user has successfully booked a desk.


Issue can happen when there are multiple users booking the same seat at the same timeslot, at the same time, which has caused multiple instances of flow to run, and finished with events created for all users, which is not be done. Only 1 flow should create event, and the rest should be declined.

Please help check this and add more functions in flow to prevent this.

Status: New
New Member

@RoterDrache92 There is already a setting to handle this. In the trigger action, open Settings, turn on the Concurrency Control and set the Degree of Parallelism to 1.

Kind regards, John

Concurrency Control
Limit number of concurrent runs of the flow, or leave it off to run as many as possible at the same time.
Concurrency control changes the way new runs are queued. It cannot be undone once enabled.