I have a project with about 300 topics. When my coworker logs-in from his computer he can see all of the topics. I am remoting into my computer using VPN and when I get into the project there are about only 40 topics-- they don't disappear from the project folder, but from the project.The topics are x-ed out on the TOC. We restored the project to an earlier version and it works when my cowoker gets in there, but when I do, the same problem happens.
So you and your co-worker are opening the same project but from different PCs?
Hopefully you are using some form of source control to operate that way.
Helpful and Handy Links
Just an FYI: we figured out what was wrong. I had reinstalled several times and this had botched my workspace profile. I got a new profile and everything is working again!