As a general rule, using "cleaning" tools on Opus's registry settings is more likely to cause problems like avoid or repair them.
I would:
- Do a config backup in Opus (Settings > Backup & Restore)
- Uninstall Opus (this will wipe the config, which is why it should be backed up first)
- Reboot
- Download and run the latest Opus installer
- Restore your config (Settings > Backup & Restore)
If you still have problems, make sure neither the installer nor any of the Opus .exe files have any compatibility settings enabled for them. In particular, if Windows is configured to make Opus think it is running on an older version of the OS then Explorer Replacement may be done in a way which isn't compatible with the real OS version.