I have been getting the CC-800 error for my Discover Bank and Discover Card accounts for about two months. The error indicates that my accounts have been deleted and must be re-added back into Quicken. Using the 'Fix-It' link is worthless as it does nothing after walking you through the process of connecting to the bank, but does not re-connect the account. I can go into each account separately and reset them, which will work for one sync, but on the next attempt, the error returns.
That process alone is very frustrating as I have 8 checking/savings / CD accounts, and one Credit Card account. Since each account must be done separately, completing them can take up to an hour.
And yes, I tried the solution of connecting my credit card to 'Discover Card' and the other accounts to 'Discover Bank' (and vice-versa) but that does not solve the problem either. And yes - I have reported this to Quicken and included a screenshot and Sanitized data file, but there is no solution yet.
I'm not sure why I'm paying for Quicken anymore.