Scheduling (F9) and the schedule log

Pressing F9 in Oracle Primavera P6 runs the critical path calculation: it takes durations, relationships, calendars and constraints and turns them into dates, float and a critical path. Most people press it without thinking. An owner reviewing a contractor's file should think about it every time, because the settings behind F9 decide what the dates mean, and the schedule log P6 can write alongside it is the quickest health check you will ever get for free. This lesson explains what F9 does, the Schedule dialog and its options, and how to read the schedule log.

Learning outcomes

• Explain what P6 calculates when a project is scheduled, and the role of the data date.
• Use the Schedule dialog in P6 Professional, including the data date options, Log to file and View Log.
• Name the main settings on the General tab of Schedule Options and why an owner records them.
• Read a schedule log and turn its warnings into review questions for the contractor.

The lesson

What happens when you press F9

F9 is the shortcut for Tools, Schedule, which opens the Schedule dialog; Shift+F9 opens Level Resources [1]. When you click Schedule, P6 uses the critical path method. It makes a forward pass from first activity to last to find each activity's early start and early finish, then a backward pass from the latest early finish back to the start to find late starts and late finishes. Float is calculated from those dates using each activity's duration and calendar [2]. Figure 1 shows the sequence.

Everything starts at the data date, which Oracle defines as the date used as the starting point to calculate the schedule [3]. Work that is not complete is scheduled from the data date forward. In a baseline with no progress, the data date is usually the planned start. At each update it moves forward to the status date.

Before a project has been scheduled, the Start and Finish columns of a not-started activity show its planned dates. After scheduling, they show the remaining early dates [4]. That is why an unscheduled file can show dates that do not follow its own logic: nobody has asked P6 to calculate them yet.

The Schedule dialog

The Schedule dialog is small, but each field matters (Figure 2) [5][6]:

• Data date. With one project open, you set the current data date here. With several open, you choose between letting each project use its own data date or applying one date to all of them [5][6]. You can also set it on the Dates tab of Project Details [6].
• Log to file. Mark it to record the results in a file. You can browse for a name and location, generate the log as HTML, and choose to overwrite or append; an HTML log cannot be appended to [5].
• View Log. Displays the results of the last run [5].
• Options. Opens Schedule Options, with General and Advanced tabs [5].

In P6 EPPM the equivalent is the Schedule button on the Activities page (also F9). Mark Display scheduling log upon completion and click Schedule Now to see the log when the run ends [7].

Schedule Options: the settings behind the dates

The General tab of Schedule Options holds the settings that change what F9 produces [8]. The ones an owner should record with every baseline and update are:

• Ignore relationships to and from other projects. If marked, external links are dropped from the calculation.
• Make open-ended activities critical. Flags activities without a predecessor or successor as critical.
• Use Expected Finish Dates (marked by default) and Schedule automatically when a change affects dates.
• Level resources during scheduling and Recalculate assignment costs after scheduling.
• When scheduling progressed activities use: Retained Logic, Progress Override or Actual Dates. Lesson 14 covers this.
• Define critical activities as: a total float threshold or the longest path. Lesson 11.
• Calculate float based on end date of each project or of all opened projects, and Compute Total Float as start float, finish float or the smallest of the two. Lesson 12.
• Calendar for scheduling Relationship Lag. Covered in Lesson 9.

The Advanced tab holds the multiple float path settings [9]. Oracle also notes that relationships to and from WBS Summary activities are ignored when P6 schedules a project [6].

The schedule log

The schedule log is P6's own report on the run. P6 EPPM Help v26 lists its sections: the scheduling settings used, statistics, errors, warnings, scheduling results and exceptions [7]. In detail:

• Statistics: number of activities, not started, in progress and completed, number of relationships, and number of activities with constraints [10].
• Warnings: activities without predecessors, activities without successors, out-of-sequence activities that started before a predecessor finished, and activities with an actual date later than the data date [11].
• Exceptions: counts of critical activities, activities with unsatisfied constraints, activities with unsatisfied relationships, and activities with external dates [12].

The P6 Professional log file follows the same pattern: the settings at the top, statistics and errors or warnings in the middle, and exceptions, including the critical activities, at the end [13]. Because the log prints the settings used, it is also a record of how the dates in a submission were produced.

Screenshot to come

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse in Vaughan, Ontario, built by Halvorsen Builders Ltd. (fictional) for Northgate Logistics Inc. (fictional) (see the Northgate fact sheet). Halvorsen's baseline XER arrives on Wed Feb 10, 2027 and is imported into the owner's NDC.SUB branch as NDC-BL00. The contractor's schedule starts at mobilization, so its data date is Mon Mar 1, 2027, the M3 milestone.

The owner's F9 routine

1. Record before you touch. Before scheduling, note the project Finish date from the Dates tab of Project Details and the dates of milestones M3 to M9 and M11 exactly as submitted.
2. Record the options. Open Tools, Schedule, Options and write down every General tab setting. Compare them with the Northgate schedule specification, which asks for Retained Logic, critical activities defined by longest path, and the successor's calendar for lag.
3. Schedule with a log. Leave the data date at Mon Mar 1, 2027, mark Log to file, save it as NDC-BL00_schedule.html in the review folder, and click Schedule.
4. Compare. If any milestone or the project finish moves, the file was exported unscheduled or with different options. Either way, it goes back to Halvorsen before anyone reviews float.
5. Read the log and turn every warning into a question (Figure 3).

Steps 1 and 2 come first because scheduling changes the file. Work on a copy if you need to keep the submitted dates intact for the record.

View the data

Log section	Item	Count (illustrative)	Owner action
Statistics	Activities	386	None
Statistics	Relationships	541	None
Statistics	Activities with constraints	9	Ask for a reason for each
Warnings	Without predecessors	4	Query 3 (M3 expected)
Warnings	Without successors	6	Query 5 (M11 expected)
Warnings	Out of sequence	0	None
Warnings	Actual date after data date	0	None
Exceptions	Critical activities	61	Review in Lesson 11
Exceptions	Unsatisfied constraints / relationships	0 / 0	None
Exceptions	External dates	0	None

What the log tells the owner

Four activities have no predecessor. One is M3, the start of Halvorsen's work, which is expected. The other three are questions: in this example, a dock leveller submittal, a roofing mock-up and an exterior lighting activity that float free of the logic. Six activities have no successor. M11 final completion is expected; five are not. Each open end inflates float and weakens the critical path, so the owner's comment letter lists all eight by Activity ID and asks Halvorsen to tie them in.

Nine constraints are not necessarily wrong. Contract milestones may carry them. But each one can create float, or remove it, without logic, so the owner asks for a list with a reason for each (Lesson 13 covers constraints). Sixty-one critical activities out of 386 is a number to remember. If it jumps at the next update, the log will show it before the narrative does.

Screenshot to come

Screenshot to come

Owner's move

• Require a schedule log with every submission. Ask for the log file produced when the contractor scheduled the file they sent, with the data date stated.
• Specify the key options. Name the progressed-activity logic, the critical path definition, the total float calculation and the lag calendar in the schedule specification. Then check the log's settings block against it.
• Turn off automatic scheduling for reviews. With Schedule automatically when a change affects dates switched off, nothing moves until you press F9 [8].
• Keep your logs. File each log with the update it belongs to. A run of logs is a cheap history of open ends, constraints and critical counts.
• Never review float in an unscheduled file. If F9 moves the dates, the float in the submitted file was not real.

Common mistakes

1. Pressing F9 before recording the submitted dates. Once scheduled, the as-submitted dates are gone from that copy.
2. Scheduling with the wrong data date. A baseline scheduled from today instead of its planned start shifts every date.
3. Several projects open at once. With more than one project open, the data date choice and the float settings apply to all of them, and the default project's settings decide critical activities [6][8].
4. Ignoring the warnings because "they are always there". Missing predecessors and successors are the most common logic defects and the easiest to fix.
5. Reading only the dates. The same file can produce different dates under different options. The settings block is part of the answer.

Quick quiz

1. In P6 Professional, F9 opens:

   1. Level Resources
   2. The Schedule dialog
   3. Check Schedule
   4. Project Details

2. The backward pass calculates:

   1. Early start and early finish
   2. Late start and late finish
   3. Actual dates
   4. Baseline dates

3. A schedule log saved as HTML can be:

   1. Appended to an existing log
   2. Overwritten, but not appended to
   3. Edited inside P6
   4. Imported as an XER

4. Which of these appears in the Warnings section of the schedule log?

   1. Activities without successors
   2. Number of relationships
   3. Critical activities
   4. Activities with external dates

5. After the owner presses F9 on NDC-BL00, M5 moves from Fri Jun 25 to Wed Jun 30, 2027. The most likely explanation is:

   1. P6 has a calculation error
   2. The file was submitted unscheduled or under different options
   3. The data date is irrelevant
   4. M5 is a WBS Summary

Show answers and explanations

1. B. F9 is Tools, Schedule; Shift+F9 is Level Resources [1].
2. B. The backward pass runs from the latest early finish back to the start and gives late dates [2].
3. B. You cannot append to an existing file when the log is generated as HTML [5].
4. A. Activities without predecessors or successors are warnings; the other items are statistics or exceptions [10][11][12].
5. B. Rescheduling a file with the same data, data date and options gives the same dates; a change points to the submission, not to P6.

Key terms

Data date

The date from which P6 calculates the schedule. Remaining work is scheduled from it.

Forward pass

The calculation from first activity to last that gives early start and early finish dates.

Backward pass

The calculation from the latest early finish back to the start that gives late start and late finish dates.

Schedule Options

The General and Advanced settings that control how P6 schedules, including critical path, float and lag rules.

Schedule log

The report P6 writes on a scheduling run: settings, statistics, errors, warnings and exceptions.

Open end

An activity with no predecessor or no successor, listed in the log's warnings.

References

1. Oracle. Tools Toolbar. Primavera P6 Professional Help, Version 26.
2. Oracle. Scheduling projects. Primavera P6 Professional User Guide, Version 26.
3. Oracle. Dates tab - Project Details. Primavera P6 Professional Help, Version 26.
4. Oracle. Activity dates. Primavera P6 Professional Help, Version 26.
5. Oracle. Schedule dialog box. Primavera P6 Professional Help, Version 26.
6. Oracle. Schedule a project. Primavera P6 Professional User Guide, Version 26.
7. Oracle. Schedule Project Log Dialog Box of the Activities Page. Primavera P6 EPPM Help, Version 26.
8. Oracle. General tab - Schedule Options dialog box. Primavera P6 Professional Help, Version 26.
9. Oracle. Advanced tab - Schedule Options dialog box. Primavera P6 Professional Help, Version 26.
10. Oracle. Statistics Section of the Schedule Project Log Dialog Box. Primavera P6 EPPM Help, Version 26.
11. Oracle. Warnings Section of the Schedule Project Log Dialog Box. Primavera P6 EPPM Help, Version 26.
12. Oracle. Exceptions Section of the Schedule Project Log Dialog Box. Primavera P6 EPPM Help, Version 26.
13. D. R. McNatty & Associates. Schedule log report (PDF).

Verified on November 6, 2026.

Next lesson in this trackCritical path vs longest path