One more question:
Is that possible duroig the testing trade two currency pairs? I want to test a mean reversion strategy, which sells one currency pair and at the same time it buys another one.
Is that possible in the strategy tester?
How to Download Historial Forex Data - Metatrader 4 Tutorial
I tried it but I could trade only the tester's currency, for the other currency pair Igot an error message: "unknown symbol name". Is there any solution for that?
In MT4 Strategy Tester, you can only trade one symbol, not multiple symbols.
You can however access data from multiple symbols, but only trade one (the one being tested). Obviously, when trading live there is no such restriction, only when testing.
For testing multi-symbol trading, you will have to use MT5 Strategy Tester.