My company is transitioning to PDM Professional.  In our current workflow, we have a Product Released state, where engineers have read-only access to files (cannot check in/out), and a Pending ECR state, where engineers have check in/out permissions so they can make changes.  We have other states, but my concern is with these ones.  For example, an engineer needs to make a change to a component of and assembly.   They transition the component from the Product Released state to the Pending ECR state, which gives them check out privileges.  They check the file out to make changes, and check the file in as needed until they are ready to transition to the next state to complete the change.  The problem with this is that any engineer that opens the top level assembly will pull in the component that's in the Pending ECR state.  If there are changes to this file that are not released yet, the assembly will reflect these changes.  I have heard that I can turn off Show Working Versions of Files to only show released revisions, but do I really have to implement a revision scheme just to control this?  If I do turn off Show Working Versions of Files for the engineering group, how will they be able to work on files that are in the Pending ECR state?  Ideally I want to protect all of the files in our Product Released state from being modified unintentionally, allow engineers to transition these files into a state that does allow them to make changes, but without these changes being visible to other engineers until the file is returned to the Product Released state.  I would like to hear how others are handling this in their PDM workflow.