Hello @Crabcake
Thank you for reaching out on the community and telling us about your issue. I do apologize for the issue you're having. Generally with reconciling you'll want to find your discrepancy from the last point you know it was correct. Is the balance off by a similar amount? One of the things you can try is to see if you may have something different from what your last statement was so that we're able to find the error. I'll leave an article down below with more things to check if the difference isn't zero that may help as well.
https://www.quicken.com/support/reconciling-accounts-quicken-mac
Once you get the chance let us know what you're able to find out and we'll see what we can do from there.
Thanks,
Quicken Francisco
First thing I'll recommend is to save a backup to revert back to just in case. You can find how to do so down below.
https://www.quicken.com/support/how-backup-or-restore-your-quicken-data
Next we'll try deactivating all of the accounts. You can do so by following the article listed down below.
https://www.quicken.com/support/deactivate-online-banking-services-quicken-accountNext you'll want to add a new account to Quicken. You can do so by going across the top to accounts > new. From here add your new account and you should see all your accounts listed after signing into the FI. Make sure it's selected as add to Quicken. once you've done this ideally the new account will be correct with no duplicates and you'll be able to correct the old one as well so you still have the data. Let us know how it goes!Thanks,Quicken Francisco