Whenever you open a work object in a modifiable mode, such as the Perform form, your requestor acquires a system lock so that no one else can alter the work object until you are done with it. If you lose your session while such a form is presented, for instance by closing the browser window, or if your session times out from inactivity, the lock is later released, normally one hour after the time the lock was established.
Locking can arise from three sources:
1. The most common reason a work object is locked is that someone else is working on it. The Lock form indicates who has the object locked.
2. The next most common reason is that you were working on this work object earlier, but then your session timed out or you lost the browser -- and the time since this occurred is still within the one hour that the lock is held. In this case, you can click the Release Lock button at the bottom of the form.
3. Rarely and briefly, a work object is locked by the operator System. This occurs when an assignment on that work object has reached its goal, deadline, or late time, and the Pega-ProCom agent locks the work object for a short time to process the service level event. If you receive such an indication that a work object is locked by the system, just close the Lock form and try again.
Suresh 2018/04/20 Database