Duplicates usually happen when the same transaction enters QuickBooks through two different paths. The most common scenario is manual entry plus bank feed import. You enter a check manually, then the bank feed brings it in again when it clears. Now you have two records for the same expense. Other causes include connecting the same bank account twice, importing CSV files that overlap with existing data, or multiple people entering the same transaction without checking first.

To find duplicates, start in the Banking section. Look for transactions in the For Review tab that match ones you’ve already added. QuickBooks sometimes flags potential duplicates with a warning, but not always. You can also run a Transaction List by Date report and sort by amount to spot identical entries sitting in your registers.

When you find a duplicate in your bank feed that matches an existing transaction, use the Match function instead of Add. Matching links the bank record to your existing entry without creating a new one. If you’ve already added both, you’ll need to delete one from the account register.

To delete a duplicate that’s already been added, go to the account register for that bank or credit card account. Find the duplicate transaction and delete it. Before deleting, verify which entry is correct. Keep the one with proper categorization, memo notes, and any attachments. Delete the one that’s just a bare bank import with no detail.

If you have duplicates in your bank feed’s For Review tab that you haven’t added yet, use the Exclude function. This removes them from the review queue without adding them to your books. Excluded transactions can be recovered later if you made a mistake.

Check your rules in QuickBooks. Automatic rules that categorize and add transactions can create duplicates if they’re too broad or if you’re also manually entering the same transactions. Review your rules and disable any that auto-add transactions you also enter manually.

For older duplicates that have been sitting in your books for months, you may need to review bank reconciliations. Deleting a transaction that was part of a previous reconciliation throws off your reconciled balance. In these cases, it’s often better to make an adjusting entry than to delete historical transactions that affect closed periods. This is where catch-up bookkeeping can help if the situation has gotten complicated.

Prevention going forward is straightforward. Pick one method for entering transactions and stick with it. Either use the bank feed exclusively and categorize from there, or enter transactions manually and match them when the bank feed imports. Don’t do both for the same types of transactions. Set clear rules for who enters what if multiple people access your QuickBooks file.

If duplicates have been accumulating for a while and your books are showing inflated expenses or weird account balances, don’t just start deleting things. Phoenix area bookkeeping services can diagnose what’s wrong and fix it systematically without creating new problems.