How to Fix ‘Expert Advisor Stopped’ Error on MT4 – 5 Common Causes

Summary: Your MT4 Expert Advisor shows ‘stopped’ or stops trading unexpectedly. This guide covers 5 common causes: AutoTrading button, chart freeze, DLL settings, error logs, and broker limits.




Step 1: Check the AutoTrading Button

Look at the MT4 toolbar. Find the ‘AutoTrading’ button (it looks like a play button). If it is red or crossed out, click it to enable. The button should turn green. Screenshot: Toolbar with AutoTrading button highlighted in green.

Step 2: Look at the Chart Corner

Check the top-right corner of the chart running your EA. A smiley face (😊) means running. A frown face (☹️) or ‘stop’ icon means stopped. If you see a frown, right-click the chart → ‘Expert Advisors’ → ‘Attach’ or re-drag the EA. Screenshot: Smiley vs frown face comparison on chart corner.

Step 3: Check Chart Freeze or Zoom

If your chart is ‘frozen’ (scrolling disabled) or zoomed in too far, the EA may not receive new ticks. Right-click the chart → ‘Auto Scroll’ to enable. Press ‘/’ on numpad to fit all bars. Screenshot: Auto Scroll option in right-click menu.

Step 4: Open the Experts Tab for Error Messages

Press Ctrl+T to open the Toolbox window. Click the ‘Experts’ tab. Look for red error messages. Common errors: ‘DLL calls not allowed’, ‘invalid lots’, ‘order send failed’. Screenshot: Experts tab showing red error log.

Step 5: Fix DLL Settings If Needed

If you see ‘DLL calls are not allowed’, go to ‘Tools’ → ‘Options’ → ‘Expert Advisors’ → check ‘Allow DLL imports’ → click ‘OK’ → restart MT4. Screenshot: Options window with Allow DLL imports checked.

Step 6: Check Broker Restrictions

Some brokers block certain EA functions (like hedging or pending orders at distance). Look for error ‘Trade context busy’ or ‘Order send error 148’. Contact your broker support or read their EA policy. Screenshot: Error 148 message in Experts tab.

Step 7: Restart MT4 Completely

Close MT4 completely (right-click taskbar icon → ‘Exit’). Reopen MT4. Re-attach your EA. This clears temporary glitches. Screenshot: Right-click exit menu on taskbar.

Reference: MetaQuotes Help Desk – Why Expert Advisor Stopped Working.