What you think about this error? It was always together with vCenter Update Manager, as long as I remember. Updates were always total pain. Always must update one by one, otherwise error, and even then you must restart every time. Sometimes HTML5 webclient version better, sometimes not. And sometimes nothing helps. - "The task failed because another task is currently in progress. Either your task, the task that is in progress, or both tasks require exclusive execution.".......And no matter what version vCenter.