‘C:\Users\AppData\Local\UnrealEngine\4.15\Saved\Swarm\SwarmCache\AgentStagingArea
v1.CC2F0757AA2598765416D9CF7469EB09B77DA0D0.mtrlgz’ because it is being used by another process.
Follow along in that part of the Wiki I made to resolve your issue. Ultimately, once you know what process is being used that prevents Swarm from using the correct port you’ll need to solve that locally on your machine. This isn’t something that I’ll be able to really walk you through, so you’ll need to use Google and a little bit of digging. Hopefully that helps you figure out what’s going on. 