Gradience Pro / Enterprise - Invalid Drive Marty Monteith Created: January 30, 2012 14:24 Updated: November 29, 2016 19:44 Follow 1. Go into Services and stop Firebird. 2. Uninstall Firebird. 3. Go to C:\Program Files (x86) and delete the Firebird folder if you have one there. 4. Uninstall Gradience and then reinstall Gradience. Click here to install.