Use a Project Deadline Without Accidentally Pinning the Schedule
A target date and a forecast finish answer different questions. When they differ, the gap is information to discuss. Forcing both fields to show the same date can make an unresolved delay less visible without making the work achievable.
Use Project desktop for Windows and an automatically scheduled practice plan. The Deadline field records a completion target and shows an arrow in Gantt Chart; Project can display an indicator when the task is incomplete beyond its deadline. Unlike a date constraint, a deadline does not pin the task's scheduled date. It can still affect Total Slack calculations.
Keep the target separate from the forecast
Make a short fictional sequence, Prepare followed by Check. Record Check's calculated finish, then enter a Friday target in its Deadline field. Keep the target and Finish visible together. Use a date comfortably beyond the initial finish so the first comparison is easy to explain.
Extend Prepare until the planned Check finish goes beyond Friday. Record three observations: the unchanged target, the revised scheduled finish and any lateness indication. Inspect Total Slack as well. Do not summarise the trial with “the date stayed Friday” unless you say which date field you mean.
Microsoft identifies Must Finish On and other finish constraints as ways to influence scheduling. Entering or viewing a deadline is therefore a different action from setting a constraint in Task Information. Inspect the actual field used before diagnosing why a task appears tied to a date.
Use the discrepancy to choose an action
Suppose the target is Friday but the current plan shows the following Tuesday. List the assumptions responsible for the gap: remaining work, predecessor availability and working time. A revised estimate, an agreed sequence change and an accepted later target are different decisions; select one only with a reason.
For comparison, inspect a separately labelled constrained copy rather than changing the real plan merely to obtain a favourable chart. Keep the original target and forecast evidence available so another person can understand the effect of the modelling choice.
Before issuing an update, confirm the target's owner and whether it is still the intended target. Report the calculated finish separately and explain unresolved variance. A warning beside an honest forecast can be more useful than a visually tidy date that obscures the scheduling assumption.
Sources: Microsoft: deadline field.