Unable to turn off FileVault in Mavericks

When opening "Security and Privacy" in Settings, a window pops up stating: "There was a problem enabling FileVault. Problems were encountered with the disk "Macintosh HD". Please turn off FIleVault, verify and (if necessary) repair the disk with DIsk Utility, and try enabling FileVault again".

Clicking "Turn off FileVault" brings up a dialog box "Are you sure you want to turn off FileVault?" Clicking "Turn Off Encryption" generates this error message: "Disabling FileVault Failed. An error occurred while reverting the disk. (Error: -69755)" and immediately afterward the same exact error message as noted at the top.

Running DIsk Utility, verified both the physical drive and the partition, both the disk and the folder permissions. FileVault problem persists. Logging out and rebooting does not clear the problem.