We were having an issue this evening deleting a print job with a printer that was connected to a printer server... we couldn't get rid of the job, and on the workstation when the job originated we started the PrintWorkflow_<6-hex-digits> and the print job went away.
What is this service for? I've never seen it in Windows, and I believe it's something new in Windows 10.
01 Answer
The PrintWorkflow_~ service appears to be related to the Per-user services in Windows 10 and Windows Server, so it's something new with Windows 10 starting at version 1709 according to the Per-user services table and section of the Microsoft post.
Applies to: Windows 10, Windows Server
Per-user services are services that are created when a user signs into Windows or Windows Server and are stopped and deleted when that user signs out. These services run in the security context of the user account - this provides better resource management than the previous approach of running these kinds of services in Explorer, associated with a preconfigured account, or as tasks.
One example of what it could be used for seems to be talked about in the Customize the print workflow post where it can customize the printing workflow experience.
Overview
Developers can customize the printing workflow experience through the use of a print workflow app. Print workflow apps are UWP apps that expand on the functionality of Microsoft Store devices apps (WSDAs), so it will be helpful to have some familiarity with WSDAs before going further.
Just as in the case of WSDAs, when the user of a source application elects to print something and navigates through the print dialog, the system checks whether a workflow app is associated with that printer. If it is, the print workflow app launches (primarily as a background task; more on this below). A workflow app is able to alter both the print ticket (the XML document that configures the printer device settings for the current print task) and the actual XPS content to be printed. It can optionally expose this functionality to the user by launching a UI midway through the process. After doing its work, it passes the print content and print ticket on to the driver.
Because it involves background and foreground components, and because it is functionally coupled with other app(s), a print workflow app can be more complicated to implement than other categories of UWP apps. It is recommended that you inspect the Workflow app sample while reading this guide to better understand how the different features can be implemented. Some features, such as various error checks and UI management, are absent from this guide for the sake of simplicity.
