Subsequent packaging attempts when Generate Chunks, Blueprint Nativization, Full Rebuild, and For Distribution are enabled will fail. The error that appears states that the AutomationTool log file is being used by another process and therefore cannot be written to.
Project: [Link Removed]
[2017.05.04-21.13.51:883]UATHelper: Packaging (Windows (64-bit)): Program.Main: ERROR: AutomationTool terminated with exception: System.AggregateException: One or more errors occurred. ---> AutomationTool.AutomationException: Failed to Write to file C:\Users\matthew.clark\AppData\Roaming\Unreal Engine\AutomationTool\Logs\D+Epic+Games+4.15\UnrealPak-2017.05.04-17.13.50.txt ---> System.IO.IOException: The process cannot access the file 'C:\Users\matthew.clark\AppData\Roaming\Unreal Engine\AutomationTool\Logs\D+Epic+Games+4.15\UnrealPak-2017.05.04-17.13.50.txt' because it is being used by another process.
This also occurred in 4.14