TrueData Velocity 2.0 Backfill

When I backfill data by clicking OK button in the bottom of Amibroker - how do I know if the backfill is really complete?

How many days of backfill data is available in Velocity Optima Plus 2.0 ?

Often when I run scan or explore or bar replay in Amibroker, it fails (Crashes) saying not enough data.

Kindly let me know how to ascertain how many years of backfill data(historical data is available) - normally to backtest nifty/bnifty people use 7 years of historical data and I am stuck with backfill issues

Please help