A wrong beginning balance on your very first reconciliation usually comes down to the account's opening balance, since QuickBooks builds that starting number from the opening balance entry rather than from a previous reconciliation. Since the opening balance entry isn't showing up in your register and you can't edit it directly, the fix is to recreate it, then check your company file for any underlying data issues if that doesn't stick.
Step 1: recreate the opening balance with a journal entry
You can rebuild the opening balance using a journal entry dated to match your real starting balance, then reconcile against that entry so QuickBooks has something correct to pull in.
- Go to Company, then select Make General Journal Entries.
- Enter the date and amount you want to see as your starting balance.
- Go to Banking, then Reconcile. Select your account, and enter the statement date and ending balance that matches the journal entry.
- In Deposits and Other Credits, select the journal entry so the difference shows $0.00, then select Reconcile Now.
Step 2: check for data damage
If the opening balance won't hold or keeps reverting, your company file may have some data damage. A quick verify will tell you if that's what's going on.
- Go to File, then Utilities, then select Verify Data.
- If you see a message that your data has failed the integrity check, go back to File, then Utilities, then select Rebuild Data.
- Run Verify Data once more afterward to confirm everything's clean.
Once your opening balance matches your real-world starting balance, your first reconciliation should pull it in correctly and let you continue as normal.
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Let us know how it goes, or if anything above doesn't quite match what you're seeing.