I've come in and found an install where data lived elsewhere and it was all controlled by this path, but there are so many times when the MAS_XXX files are not enough to restore functionality without MAS_System, MAS_Users, etc. and I don't recall whether those were in the alternate location or not, but it had been running well enough before we came along (and moved it back into the MAS90 folder). The installation guide (yes, I looked at it!) says this: If company data is moved to a different data location using Library Master Company Maintenance, the same drive letter must be used
from all workstations to point to the alternate folders, including the server if it is used as a workstation.