SummaryWhen trying to upgrade Nintex Workflow the following error is being displayed,NintexWorkflow2013core.wsp 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.
Solution1. Run the command below from a command prompt using the name of the .dll that was provided in the error text during the upgrade. This will provide you a list of the PID's associated with the tasks that are currently using the dll: tasklist /m [dllname].dll (can be formatted like tasklist /m nintex.workflow.dll for example)
2.After getting the list of PID's you will want to run the taskkill command below to stop any processes that are currently using the .dll: taskkill /pid [PID1] /pid [PID2] (IE taskkill /pid 1234 /pid 4567 /pid 7890)
3.After stopping these processes, you can either go in to Central Admin and try redeploying the solutions or you can rerun the installer.
4.After you have confirmed that the .dlls have been recreated properly on the affected server, reboot the server (this will allow the PID's to restart) and you can finish following the product update guide to complete your installation.