The shape classes are disappeared in the Shape dialog. Also, there are no regional shape catalog present in the Shape Catalog dialog.
Please follow the below steps to resolve this problem.
1. Open the Configuration Variable dialog by searching the same in the Search Ribbon.
2. In the Configuration Variable dialog, search for the variable PS_SHAPESDATABASES and check the Expansion of this variable that at which location this variable is pointing. The default location for all the shapes catalog is "C:\Program Files\Bentley\ProStructures CONNECT Edition\ProStructures\Default\appl\Shapes".
3. Here, we need to mention the correct path for the shapes catalog where we have stored all of these this maybe a default path or a custom path.
4. Once we have entered correct path then re-launch the application and open the Shape dialog to check. Now, you can find all the shapes catalog here.
In this way, we can resolve this issue.