I have a year-old old transaction which shows up when trying to reconcile my credit card. This is for a transfer I made from my checking account to pay my credit card

Welcome to the QuickBooks Community, @psconsult.

Making sure that you have the correct and updated transactions is really necessary. To further help you with this, I suggest reaching out to your accountant. It's best to ask for assistance from them since this involves a year-old transaction. They can either check the transaction so it will be removed permanently or manually reconcile it so it will no longer show on the reconciliation screen. If you're not affiliated with one, you can use our Find an Accountant tool.

I've also got you this helpful article to further guide you in reconciling your accounts: Learn the reconcile workflow in QuickBooks.

Once reconciliation is done, you can pull up a report to have a copy of it for the previous period. This is also a big help so you can avoid issues in doing future reconciliations.

Please know that I'm always around here in the Community to help. Just post a reply below if you have further concerns about reconciling your accounts in QuickBooks. Have a good day.