Corrupt files will give erroneous circular relationship error messages. If
you have files that were originally created in MS Project 2003 and you are
now using 2007, you probably have corrupt files.
To start testing for a circular relationship, build a consolidated schedule.
Expand the consolidated schedule to show all tasks then open the Network
Diagram view. If you can see a network diagram, you do not have a circular
relationship. I have an Excel file that is supposed to identify circular
relationships, but I have not tested it. I can email it to you if you want to
try it.
Here's a manual method of indentifying files included in a circular
relationship. From the consolidated schedule where you can't view the network
diagram, delete one inserted project then try viewing the network diagram. If
you can see the network diagram, then the last file deleted is included in
the circular logic. Undo the delete then delete another inserted project and
display the network diagram. Repeat for all files. You will probably find
that at least three files are included in the circular logic. If this
technique does not identify any files, you have multiple circular paths. For
multiple circular paths, leave the files deleted from the consolidated
schedule. In a new file, insert two of the identified files and view the
network diagram. If you can't view the network diagram, in one file, collapse
half of the summary tasks and view the network diagram. If you can view the
network diagram, at least one task that is now hidden is included in the
circular logic. You should be able to identify one task included in the
circular logic within ten reductions of the task population. Once you find
one task, try using the relationship diagram to trace the logic from that
task.
Please describe the method you are using to back up your files. If you have
two linked files open and use "save as" to back up one of the files, then
save the linked file back to the server, you can create cross linked files.
You probably still have the link to the original file that you "saved as", so
you should be able to break the link to the backed up file without losing
anything. In a task table insert the project field and find the external task
that is in a backup file. Split the screen, right mouse click on the Task
Form and select Predecessors and Successors. In the top window, go to the
task that the backup task is linked to and verify that the description for
the backed up task is duplicated in the Task Form. If so, in the top pane,
insert uniqueid predecessors or uniqueid successors as appropriate. Verify
that the UniqueId is the same for the on- and off-server tasks. You can
safely delete the off server link once verified.
To avoid circular relationships, avoid summary task logic, negative lag and
set the option to show the links between projects dialog box on file open.
Use begin and end milestones instead of summary task logic, or link directly
to subordinate tasks. If you must have summary logic, if you have
predecessors to summary tasks, do not have any predecessors to subordinates
of those summary tasks. If you have successors to summary tasks do not have
successors to subordinates of those summary tasks. When the links between
projects dialog box opens, you have two files out of synch. Be sure to
resolve the differences then save all involved files before closing any.
