The Damage Control Checklist for Project Schedules

Written on . By CPM Solutions

It just isn’t easy when you inherit a project in P6 with thousands upon thousands of activities and you’re the one asked to tidy things up and see why the schedule has not been calculated properly. Although it’s convenient to have limitless data storage in the software, the reality of cleaning up someone else’s mess of a schedule is the worst of it. It could take days or weeks to clean up even a project with a few hundred activities. There is no ultimate “undo” button within P6 (yes, the undo feature does exist, but it won’t help you this time) that can erase the logic errors and the miscalculated progress or values of activities.

Once a schedule gets handed down to you, it may be difficult to decipher as some planners have their own methodologies and ways of manipulating P6, which could drastically affect the way the schedule is calculated. The hard way for a company to learn that they should have properly trained planners and schedulers, is when they run into a schedule that does not accurately reflect the project itself.

We’ve put together an essentials checklist of what to look for when the going gets tough…


Do you have the right tools and resources to help you identify the bigger picture? Being able to do this will give you an idea of what the project should look like vs. what it currently looks like. Things to keep in mind:

– Does the WBS make sense? Are there too many levels or too few?
– If milestones have been underutilized, add them in to visually identify important dates
– If the schedule has too many activities and if activities can be combined and merged together

Use layout out options and filters to help you find what you’re looking for:

WBS Summary


– Right click and select “Collapse To” for WBS level option to minimize to (in this case, we can select WBS Level 1).
– In your Group and Sort display options, make sure “Show Group Totals” is checked off.
– Some suggested columns: Activity Count, Start, Finish, Original Duration, Total Float, etc. Depending on what else you are looking for, you may find some % complete columns useful.
– Save this layout if you intend on using it again.

Grouping by Constraints


If you want to group by activities with constraints, group your bars by “Primary Constraint”. For easier viewing, you can check the “Show Group Totals” box in combination with the “Activity Count” column.

Filtering Open-Ends Visually into Your Schedule

Although your schedule log will tell you which activities do not have either predecessor or successor, a visual way of seeing this on the spreadsheet in P6 is to create a filter:

– Where: Make sure “Activity Type” is not equal to WBS Summary (additionally, you can include Start and Finish Milestones as well).
– And: When “Predecessors” are equal to leave value blank or when “Successors” are equal to leave value blank.


1. Thoroughly understand the project and its scope. Are you privy to the following information?

– Project scope and charter
– Approved project budgets
– Scope creep documentation or notes
– Rough plans worked outside of P6 (could be drawings or diagrams)
– Documentation of actuals or progress reports

Why: Any and all supporting documentation or notes can help you undo things like mandatory constraints which can create logic errors. Identify as many problems as you can first and make sure you document your findings as your own “to fix” checklist. Keep a tab on documents that had a hand in creating the schedule and possible information from paperwork that was input into it – these may become useful later if you need to re-enter data.

2. Create a copy of the project and schedule it (F9). Check the schedule log for additional errors to give you more hints on what could be fundamentally wrong with the logic and why dates are not matching up.

– Are there any baselines from the beginning of the project? If so, restore it as a project first and make a copy of it to compare and work on.
– Do any of the previous users working on this project have exported copies of this project? Find anything that can help you backtrack through the disaster!

Why: it is ALWAYS a best practice to create a copy because you may need to try reworking the plan in different ways. Unfortunately for some, not all schedulers practice this. If you’re one of the lucky few, you may be able to access back-ups of the project plan during its pre-scheduling state.

 3. Check dates – spot any overall errors or inconsistencies!

– Project start date: make sure the project start date is accurate.
– Must Finish By date and Planned Finish date: this is an overall project constraint that does not affect logic, but it will – give you a parameter to fix the schedule within. Check to see if the planned finish is before or after. You should usually be able to tell right away from the critical path on the Gantt chart.
– Data date: make note of when the project was last updated to give you an indicator if your project has actuals or if it is still in the planning stage.

4. Check Calendars, reassign them if necessary to the project and specific activities, and reschedule (F9).

– Was a global calendar being used? Has it been changed since it was first linked to the project plan?
– What calendars are being used for activities?
– Make sure holidays and time off are accurate in the calendars.
– Look at your weekly calendar hours and time periods to make sure they are correct and match the current calendar that you have.

Why: Calendars will affect duration and dates, depending on the available work time and activity type. Check what the default calendar is on the projects page and add a “Calendar” column to see exactly what calendars are assigned.


5. Check Constraints – those who are not used to scheduling in P6 or have not been properly trained may try to control start and finish dates via constraints. This tends to muddle up the logic within the schedule. Use the schedule log to help identify where the logic errors lie and which activities have constraints.

– If possible, reduce the number of constraints or utilize any given documentation to make sure the constraint is justified. If duration and relationship can be used instead, adjust accordingly.
– Have any mandatory constraints been used?

6. Check Durations

– What duration type is selected for the activity in question?

Why: Durations and duration type will often affect the priority in which the schedule calculates the number of days it takes for the activity to finish. Be wary of physical % complete type as well, as improper progress updating for this type can continuously stack durations for activities with this.

7. Check Relationships

– Are there any redundant relationships?
– Check for activities that do not have relationships
– Open ended activities

Why: Relationships determine start and finish dates once you have proper calendars and durations assigned to all activities. Relationships are also the key to establishing the schedule logic. You can add “Predecessor” and “Successor” columns to your table to quickly eyeball all activities and what relationships have been assigned.

8. Check User Preferences – sometimes the problem could be as simple as having the wrong duration units being displayed.


9. Check for out of sequence updates – if the schedule has already been progressed, some activities may have been progressed after activities that have not started at all.

– Look for documentation as to why the update occurred
– Look at the schedule log for out of sequence activities
– Use the “options” button in the scheduling menu to either retain or override the logic
– Adjust relationships if you decide to retain logic and reorder the activity instead


Most discussion that I’ve listened to of planners/schedulers when facing a problem schedule will sometimes involve the brutal choice of creating an entirely new project and reworking everything into it. The decision making ball is in your court and you will have to decide if examining and dealing with the current schedule will cost more time and money than actually copying out a new one.

Good luck if this article is relevant to your current situation!