If you create an empty folder on your desktop, then right-click that and choose the Open in Directory Opus option, does that folder open OK?
If you have a config backup, uninstall and then reinstall is worth a try, to see if the problem is still there with the default config.
How to backup or locate your Opus configuration (Simple) has information on doing config backups, both using the wizard and manually by copying files.
If the problem is not solved by using the default configuration & toolbars, then it is likely caused by shell extensions or similar 3rd party components, or by a particular file in your startup folder (which the empty folder test above should rule out). Crash, exit or high CPU when viewing certain directories has suggestions along that path.