Troy,
You may or may not be aware that dynamic structures in Project (e.g. master/subproject) are prone to corruption. The rules are, never rename, move, overwrite or "save off" to another location, any of the files in the structure. Ideally, all files should
reside in a common folder on a local drive and not be operated over a network.
You mention "schedulers" (multiple?) and 20 or so subprojects. With that many users and files, I'd say the chances of someone violating the above is very likely. If Project cannot find a subproject (from the master), then the path is probably corrupt. If
the files ARE operated over a local network, a network glitch can easily corrupt the link structure.
My suggestion is this. With that many users and subprojects, creating a static master instead of attempting to monitor/maintain a dynamic master is a much better, safer approach. You will have to rebuild the static master anytime you want to see the whole
structure, but you won't be subject to the probability of corruption.
My thoughts.
John