I've recently been upgrading users to the latest RC; many get a Debug Close program error when trying to run RC. I've tried resolving it by uninstalling the newest version and rolling them back to a version that's worked for them before.
i believe you may have to make sure all ring central softphones are uninstalled, and the regedit is cleared of any ringcentral things. i did this and reinstalled the new version after restarting computer and it cleared things up. But still don't have all the features i used to have!