One user cannot view Search or Index results

We are publishing in RoboHelp 9. The output is fine. Everyone else can view the output file.

But one person is having issues. He can view the Contents button just fine. If he clicks on Search and enters a search term, nothing comes up. Index is even worse. Not only does nothing come up when he enters a term, but the Index keywords does not automatically display for him when he clicks on the button. These behaviors are inconsistent with everyone else here.

My first thought was that maybe there is a permission issue, but he can access the help file. He can view the TOC. There is something preventing him from seeing the Index and Search results. Any ideas what could cause this?

Kevin