Amy U --
I just noted in your previous question that your organization is using
Project Server. Now I can tell you why I believe the resources are
disappearing. If the resource assigned to a completed task deletes the task
on his/her My Tasks page in PWA, and then the PM unwittingly APPROVES the
Delete Assignment Request, Project Server 2007 will REMOVE the resource from
the assigned task in the Microsoft Project file. If this is actually the
case, then your team members and your PM are screwing up the process. I do
not recommend that team members ever delete tasks on their My Tasks page in
PWA, nor do I recommend that PMs ever approve Delete Assignments Requests.
Why don't you ask the PM in question if my description is what he/she and
his/her team members have been doing in this project? Let us know what you
find you.