Planner answers
How do I fix out-of-sequence activities in Primavera P6?
Short answer: An activity is out of sequence when it has progress but its predecessor has not finished (FS) or started (SS). Fix the logic to match what really happened: change the link to SS or SS+FF, record the predecessor's actual dates if it is in fact done, or split the activity. Then schedule (F9).
Out-of-sequence progress is the most common reason a P6 critical path suddenly jumps. With retained logic (the default), P6 keeps the remaining work of the progressed activity waiting until its predecessor finishes, so the finish date can move for no real reason. With progress override the remaining work ignores the predecessor, which can hide a real dependency.
Step by step
- Find them: in P6 run Tools → Schedule → Log to file and read the out-of-sequence section, or drop the XER into the free problem finder, which lists every link with a suggested fix.
- For each link ask what really happened. If the predecessor is actually finished, record its actual finish. If the two activities overlap in reality, change FS to SS (and add FF if the successor cannot finish first).
- If only part of the successor could start, split it into the part that started and the part that still waits.
- Schedule (F9) and check the critical path again.
Never fix out-of-sequence progress by switching the whole project to progress override just to make the dates look better: Engineers check the scheduling options.