Primavera P6: Cannot change Remaining Duration of an Activity

Problem

When we change the Remaining duration of an activity, it keeps reverting to the original value.

Change the Remaining Duration value of an activity

Reason & Solution

There could be two reasons of this problem:

1. There is an “Expected Finish” constraint on the activity. When using an Expected Finish constraint, the remaining duration is calculated as the duration between the Data date and the Expected finish constraint date. To allow for manually updating the remaining duration, we need to remove the Expected finish constraint.

Remove Expected Finish constraint to be able to change the Remaining Duration

2. There is a driving resource assigned to the activity. When using driving resources, we need to update the resource duration or resource actual usage in order to update the activity remaining duration. To allow for manually updating the remaining duration, we have to remove the “Drive Activity Dates” flag on the resource assignment.