When you run the Content Classification installation program and select Custom, you must select the components to install. If you select all components except for "Server and Client Components", Classification Workbench is not installed correctly.
When you try to import files from the file system into Classification Workbench, an error occurs and Classification Workbench must be closed.
Resolving the problem
To correct the problem, run the installation program again and select only the Classification Workbench option.