data backup

I have amibroker 5.5 when I have Intraday data for suppose NCC script. from 20.3.2015 to 25.3.2015. Now when I backfill the data from external data feeder software (RT) to amibroker from 26.3.2015 to 30.3.2015 . It dont update it , it replace new data from old data. So data from 20 to 25march...

Hi guys Im new to trading, traderji and amibroker so I require a lot of help from senior members of traderji to clarify my doubts. I have downloaded data 10yrs EOD data to amibroker with Getbhavcopy s/w and i have adjusted for symbol change for the data too and I have done this in my laptop...