After MetaQuotes update of MT4 somewhere around build 880, Strategy Tester in offline mode throws invalid trading volume errors (error number 131) when a backtested EA tries to open a trade. This is most likely related to the symbol specification data that is dynamically loaded from the broker's server when the terminal is connected. Conversely, when the terminal is offline it no longer holds information about the minimal, maximal trade volume as well as the volume step. All of this is used to validate data sent by the OrderSend function.

To our knowledge, the last known MT4 build suitable for offline backtesting is either 842 (beta), or 840 (production). Therefor, the only way to backtest custom charting is to use tick data backtesting or the following workaround for this particular problem. In order to use the workaround, you'll first need to download terminal-842.exe from, unzip and and copy it into your MT4's installation folder.

Now, simply follow the backtesting instructions for RangeBars, Renko or PointO charts up to the point where you need to shutdown MT4 and restart it.

After shutting down MT4 you'll need to execute terminal-843.exe /skipupdate instead of terminal.exe. The (/skipupdate) parameter is very important!

It will be helpful, if you create a shortcut file and define the target as: "YOUR MT4 INSTALLATION DRIVE AND FOLDER HERE\terminal-842.exe” /skipupdate
You will be able to use the shortcut to start MT4 and prevent it from updating terminal build 843 to the latest version (newer versions will prevent you from using this workaround).

The rest of the process does not change.