SIS - 'Resource in Use' Error
This document explains how to resolve the SIS error: "The resource you are trying to schedule is currently in use. Try your save again. If after 3 attempts you still cannot save, contact your system administrator."
Resource Queue Message
There is a "Resource Queue" in PeopleSoft's class scheduling system. This Queue is meant to prevent users from double booking facilities, and tends to appear more frequently during Final Call and/or when updating a meeting pattern. When two people attempt to schedule facilities at the same time, the data is locked in the Resource Queue by the first user, and this message will appear:

This lock should normally be resolved in a few minutes when the first user completes his work.
If the lock lingers more than five minutes, it is probably 'stuck.' Users should contact Curricular Services to unlock it.
