Must Finish by (Project Constraint, Not Data Date)

What the field is

Oracle Professional Dates tab: “A date constraint placed on the project end date.” EPS: “The optional date constraint you can specify for the project end date.”

XER: PROJECT.plan_end_date (Oracle label: Must Finish By). Planned Start is plan_start_date. Schedule Finish is scd_end_date. Last Recalc Date is last_recalc_date. Do not swap them.

Oracle Activity Dates: late dates are calculated from the end of the project backward. “The end of the project is determined as the latest early finish date of all activities, unless the Must Finish By constraint has been applied to the project in which case that date is used as the end date of the project.” Work Planning: if entered, it is used as the project late finish date.

So: blank MFB → backward pass from the latest early finish. MFB set → backward pass from that date. If the network cannot finish by MFB, late dates sit earlier than early dates and you see negative total float. That last sentence is the usual planner read of those two Oracle facts; Oracle does not print “MFB causes negative float” on the pages cited here.

What it is not

• Not Data Date. Data Date is “the date used as the starting point to calculate the schedule.”
• Not Schedule Finish / Finish (latest early finish from the last schedule run).
• Not Anticipated Finish (planning-stage user date on WBS/EPS/project).
• Not Expected Finish (activity-level typed forecast).
• Not an activity Mandatory Finish. That is TASK.cstr_type on one row.

Microsoft Project has no project-level field named Must Finish By. Status Date is the Data Date analogue, not this. Do not map plan_end_date to MSPDI StatusDate or StartDate. A Finish No Later Than on a finish milestone is a common practice analogue, not an identity. Unverified as a converter rule.

23-10-CE-LIVE data date is 31-Jul-26 17:00. Whether that XER has Must Finish By populated is not claimed here.