Avoid importing the same bank period twice.

Create a company-file backup before adding a new bank statement. A recovery point is more reliable than trying to identify and remove a large duplicate batch afterward.

Keep the statement start and end dates beside the downloaded file. Do not combine overlapping exports unless you have checked every overlapping date.

QBO and OFX files may contain transaction IDs that importing software can use to identify repeats. CSV files often lack a stable identifier, so period tracking matters more.

The same date, description, and amount can be a legitimate repeated charge. BankFileKit flags that pattern as a possible duplicate in CSV/Excel sources, and flags repeated identifiers or repeated transaction patterns in supported QBO/OFX statements. It never deletes the row automatically.

For a new workflow, import the same fictional test file twice in a blank company and record what QuickBooks does before using a live file.

Compare the number of source transactions with the number of valid preview rows. Resolve missing or duplicated rows before download.

If a duplicate rule appears wrong, make a synthetic file with invented merchants, dates, and amounts. Do not email the original bank export.

See OFX vs QBO vs CSV for the differences between structured transaction IDs and a plain spreadsheet table.