Solution(s) fail to deploy during a Nintex upgrade because a file is being used by another process.
When upgrading Nintex Workflow, some Nintex solution(s) may be in an 'Error' state with the following error:
The process cannot access the file 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\Bin\[NintexDLLName].dll' because it is being used by another process.
From a command prompt, run the following command (using the name of the .dll that was provided in the error text) to obtain a list of the PID's associated with the tasks that are currently using the dll:
tasklist /m [dllname].dll
Run the following taskkill command, using the PID list from Step 1, to stop any processes that are currently using the .dll:
taskkill /pid [PID1] /pid [PID2]
After stopping these processes, either go to Central Admin and redeploy the solutions or run the installer again.
After confirming that the .dlls have been recreated properly on the affected server, reboot the server and finish following the product update guide to complete the installation.
The copying of this file failed: Bin\NintexWorkflowStart\Autofac.dll. The process cannot access the file 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\Bin\NintexWorkflowStart\Autofac.dll' because it is being used by another process.
See the following references in Microsoft TechNet for the tasklist and taskkill commands: