But... in at least two instances this option is useful: backfilling much more bars following settings change (when you enlarge 'number of bars to load' in File->Database Settings dialog You should drive backfill for symbols which were backfilled Earlier with more compact variety of bars) cleaning up bad ticks (any https://martinyaxxt.madmouseblog.com/15661794/5-simple-statements-about-data-feed-for-amibroker-explained