Short answer
Balansix flags bank lines that resemble existing activity so the practice can review them before creating duplicate accounting records.
What to check
- Compare the transaction date.
- Compare the amount.
- Compare the bank description or reference.
- Check whether the source statement genuinely contains both transactions.
- Keep a legitimate repeated payment or receipt even where the description and amount are identical.
What should happen
A true duplicate should not be posted twice. A legitimate repeated transaction should remain available and should not be discarded simply because the values look similar.
If you are unsure
Use the original bank statement as the source of truth. If the warning cannot be resolved from the statement, leave the item for review rather than deleting it.
Why duplicates happen
The usual cause is overlapping statement periods: the same transactions are imported twice when a new file starts before the last imported date. Re-importing a corrected file without removing the earlier import has the same effect.
Not every match is a duplicate. Two identical standing orders, repeated card payments of the same value on the same day, or regular fixed receipts can all be genuine. The bank statement is the deciding evidence.
Frequently asked questions
How do I avoid duplicates when importing?
Check the last imported date for the bank account and make sure the new file starts after it. Import each statement period once.
Should I delete a line flagged as a possible duplicate?
Only after confirming from the original statement that it really is a duplicate. If it appears twice on the statement, keep both.
What if a duplicate has already been reconciled?
Follow the reconciliation lock guidance to reopen the control before correcting it, then reconcile again.