False duplicated transactions while importing bank statement

I’m trying to import a simple csv file but some of the transactions inside Manager recognise them as already imported.
What are the rules in order Manager to evaluate a transaction unique or vise versa.

If you have manually entered a transaction, then when importing, if Manager matches that same transaction then it will recognise this and not import the duplication.

I understand that, but what is the rule for manager to understand that a specific transaction is same as a previous one. etc: the amount, description, reference ??

Don’t know what parameters are built in to the programme but I would suspect Date & Amount, as they are the only two which are in common between both Manager and the Statement.

I almost responded with the same information as @Brucanna earlier. Date and Amount are obvious. Description is not likely to be a reliable indicator, as banks often have their own undecipherable ways of listing transactions, and those are almost certainly never going to match what you’ve entered. Whether some kind of reference number is checked is dubious, since Manager wouldn’t know which of several possible numbers on the bank statement to match against several alternatives on your end. Very probably, the bank assigns transactions numbers you have no way of knowing until the statement is downloaded.