FPGA Is Busy Error When Deploying a VeriStand™ Project

This error occurs when another application or process is already connected to the FPGA and holding an active session open. Because the FPGA is in use, VeriStand cannot download the bitfile during deployment. To resolve the issue, close all other sessions that may be accessing the FPGA.

Try the following steps:

• Close LabVIEW if you previously ran the FPGA VI using Interactive Mode or opened a VI that interacts with the FPGA. Closing LabVIEW releases any active FPGA references created through the LabVIEW FPGA Interface.
• Close any other applications or custom tools that may be using the FPGA Interface C API. This includes Real‑Time applications running on the controller that open FPGA references.
• Disable or remove any VeriStand Custom Devices that interact with the FPGA early in system deployment. Some custom devices may attempt to open the FPGA session before VeriStand is ready to download the bitfile.
• Reboot the CompactRIO controller to guarantee that all FPGA sessions are closed. Rebooting releases any orphaned references left open by deployments, custom devices, or background processes.
• After confirming that no other sessions are connected to the FPGA, deploy the VeriStand project again.

If the error persists after performing these steps, verify that no background Real‑Time processes or services are launching automatically and opening FPGA references during startup.