The WebCenter FileStore folder needs to be a shared folder. In case this folder is not correctly shared for some reason, icons and thumbnails may appear missing in WebCenter.
Symptoms
The Project status icon is missing for all Projects.
Documents are not loading in the Viewer.
The Troubleshooting tool does not reveal problems.
Solution
To resolve the issue:
Check if the FileStore folder on the Application server (or your preferred FileStore location) is still shared. If not, make sure it is shared again.
Check if same problem occurs while accessing WebCenter directly from the Web server. If not, make sure the FileStore folder is accessible from the Web server.