It's been over a year since I started getting the error when running One-Step update. It would download transactions but wouldn't synch Quicken with my 3 Vanguard portfolios. I don't know how many times I reset the accounts to no avail. Then it dawned on me that I had an old Vanguard account in Quicken that was hidden but still open, (no balance). I unhid it and discovered it was still connected. I deactivated it and the error code went away!