Direct answer
In MT4, an Expert Advisor (EA) can look “blue” for interface reasons rather than as proof of correctness or profitability. Blue usually reflects a state in the MT4 window you are viewing—such as selection, enabled/disabled readiness, or a particular visual indicator tied to the editor or terminal. The key point is that color alone is not a reliable measure of whether the EA is trading, how it is configured, or how it will perform.
Explanation of what can make an EA look blue
MT4 uses color and highlights inside its editor and terminal screens. Depending on where you see the blue (for example, in lists, status lines, or the MetaEditor view), the same EA may appear blue because:
- The EA is selected or highlighted by the user interface.
- The EA’s component is enabled/loaded in the terminal context.
- The EA is marked in a way that helps identify its state (for example, ready to run vs. not running), based on current platform conditions.
However, an EA’s real operation is determined by its runtime state (whether it is attached to a chart and allowed to run), its input parameters, and the strategy logic inside the code. None of that can be concluded from color alone.
Example checks you can do independently
To understand what “blue” means in your exact situation, verify observable signals:
- Confirm the EA is attached to the intended chart and that automated trading is permitted in the platform settings.
- Check the terminal/account journal or experts log for messages when the EA is running (errors, compile/runtime notes, or start/stop events).
- Compare the chart behavior with the EA’s code logic and input settings (for example, whether the EA waits for a condition, uses filters, or requires a timer/event).
If you see no log activity and no evidence of the EA responding to events, a blue appearance likely reflects only a UI state.
Limitations and risks
A color cue like “blue” is context-dependent and can differ across MT4 screens and workflows. Even when an EA is enabled, trading outcomes are uncertain and depend on market conditions, settings, and code behavior. Treat the visual color as a starting clue, not a conclusion, and rely on logs and runtime state checks to verify what the EA is actually doing.