Do More Than Manage
Gord Schmidt's Ideas for Doing More with Microsoft Project Server
Summary Task

Resolving circular references in MS Project

A customer presented me with a project plan with thousands of tasks. Somewhere within that large list of tasks lurked one or more circular relationships and the error message did not help. The task to which the error message was pointing was not, as far as I could tell, part of the circular relationship.

No calculations can be performed now.
 There is a circular relationship in task ***. The successors of this task refer back to this task or its predecessors, causing a circular reference.
 To remove the link that is causing the circular reference, select the two tasks that are causing the circular link, and then click Unlink Tasks on the Standard toolbar.

I started scanning the project but there were so many defined dependencies I quickly gave up on that approach.

Instead I added the Predecessor column and an unused custom text column to the Gantt view and bulk copied the contents of the Predecessor column into Text20. Next I removed all of the predecessors with one massive delete resulting in something like the following:

Predecessors and Text20

Next I copied the contents of Text20 back into the Predecessors column and was presented with a series of error message that clearly identified the dependencies that were causing the problems.

A pasting error occurred on ID 1025 in the Predecessors column.
 If you want to link the two tasks, outdent the subtask to a summary task, and then link them.
 To cancel this paste operation, click Cancel.
 To continue pasting with additional error messages and ignore this error, click Yes.
 To continue pasting with no error messages in this column, click No.

Whew! That was a boring afternoon avoided.

Posted by Gord Schmidt on Thursday, May 01, 2008 | Permalink | Resolve