I have deployed a wsp SPSolution.wsp on a web application. After a few days I needed to update this wsp, so I made changes in the solution and published the wsp. Now when I executed Update-SPSolution command. By looking at the status which changed from "Deploying" to "Deployed" in solution management in central admin, we can assume the wsp got updated. But I didn't see the changes I made so after thinking a lot I re-published the wsp and re-executed update command. And voila! I saw the error
update-spsolution : A deployment or retraction is already under way for the solution "SPSolution.wsp", and only one deployment or retraction at a time is supported.
Now, I don't see any deployment or retraction under way for any solution. In fact I confirmed it via
stsadm -o enumdeployments which shows
<Deployments Count="0" /> count=0.
That means no deployment/retraction is under way, right? So, do you have any idea what might be happening over here?