in the seti@home project, their software had a feature where you could create afile with a specific name, and when the current workunit was completed, it would upload the results and not download a new workunit. That way you could complete a workunit, and resign a computer from the project without wasting the download and start processing of a new work unit.

There used to be a bug in the profile setting on the web site here where you could specify a disk usage so low that you would never get new workunits after you completed the current one. I spent a couple of days trying to figure out why I couldn't get a new workunit, turned out to my operator error when trying to select the largest disk size, I accidentally selected the smallest. The WCG folks appear to have corrected that bug, so you can't do that anymore.

So, there is currently no way to complete a work unit and not download another. If you download a workunit and do not complete it, the server will send it to multiple agents anyway, so not completing a downloaded work unit will NOT cause that workunit to never be processed. Or, reworded to remove all the negatives, all th work units will get processed regardless of what happens on any one individual agent.

If you want to minimize the amount of time that your PC spends processing the new work unit before you just turn it off/deinstall the agent, then create a new profile for that computer, and set the schedule for that profile to be some really small time window, one hour per week or some such thing. Then when the current work unit is completed, it will download another and update the profile, and won't process much at all before you notice that it's idle and deinstall the agent. That's what I'm going to do. I have a really slow machine that isn't worth the electricity just to run WCG, but I want to finish a work unit before I shut it down.

If you just need to deinstall the agent today, right now, then just do it. The work unit that it is processing will be processed by a number of other agents, You won't get points for the partial incomplete processing, but it won't damage the overall project.