MS Project External Predecessors Not Working

Question

We've been using MS Project files from different sections of the office linked together for a while and all of a sudden we can't add external predecessors to the file. When we add the file file path to cell and try to move on it erases the file path.

Answer 1

If you can narrow the issue to one file and multiple users are working across a network, it's entirely likely the file has been corrupted.  You may need to rebuild the file (save as XML and then import into a new file).  You'll need to create the the external links.

Answer 2

The files all reside on a network share, and when someone got into the file first thing this morning it worked. As the day goes on and individuals work in the separate files this issue seems to come up again and again in one particular file (this has links that go both ways in a chain).

Answer 3

Can you add the external predecessor (or successor) by combining into a master (create a blank project, Insert Project) and then link?

There is a limited on external links - but if I recall its 999.