In this article i will show you how to download history in MT4 terminal and in this way you will get more precise results and you will avoid errors while backtesting robots or indicators. If you're testing without history data you will get mistaken results, so better download data for your desirable forex pairs. It has to be done only once in terminal, if you have more than one platform, so do it the same process in them all. Now is popular to download data from some unverified websites and use that data. Most of them are very proud of it, cause strategy tester shows 99% history quality, also they use this trick to sell robots better. Unfortunately those results are much worse than normal testing, so i recommend don't believe it. In MT5 you don't need to do anything by yourself cause history data is downloading automatically.
1. Open your MT4 then > tools > history center
2. In this example i chosen EURUSD. Select your pair and press twice on each time frame, wait until the field will change the color and do this process for each time frame 1 minute, 5 minutes, 15 minutes, 30 minutes, 1 hour, 4 hour, daily, weekly, monthly until all icons are green/yellow, then press on the pair icon above (in this example EURUSD) and press a button download. That's all. Be patient If your internet speed is low , it takes some time. After that your're ready for backtesting.