How to Install an Expert Advisor in MT4

Before you start

• MetaTrader 4 installed and logged in — see How to Install MetaTrader 4.
• The EA's MT4 file: a compiled .ex4 (and sometimes .mq4 source). Extract .zip downloads first.
• Any extra files the developer supplies: .set presets, or files for the Libraries folder.
• Ideally a demo account for the first run.

What you'll learn

• Install the EA files in the correct folders.
• Attach the EA with live trading allowed.
• Confirm in the logs that it's running.

Steps

1. 1

   Step 1: Open the data folder

   In MT4, go to File → Open Data Folder, then open MQL4 → Experts.

   Mark as done: Open the data folder
2. 2

   Step 2: Copy the EA files

   Paste the .ex4 (and .mq4, if provided) into Experts. Put library files the developer mentions in MQL4\Libraries and .set files in MQL4\Presets.

   Mark as done: Copy the EA files
3. 3

   Step 3: Refresh the Navigator

   Open the Navigator (Ctrl+N), right-click Expert Advisors and choose Refresh, or restart MT4.

   Mark as done: Refresh the Navigator
4. 4

   Step 4: Attach it to a chart

   Open a chart for the symbol and timeframe the documentation specifies and drag the EA onto it (or double-click it).

   Mark as done: Attach it to a chart
5. 5

   Step 5: Allow live trading

   In the properties window, open the Common tab and tick Allow live trading. Only tick Allow DLL imports if the developer says the EA needs it and you trust the source.

   Mark as done: Allow live trading
6. 6

   Step 6: Set the inputs

   On the Inputs tab, adjust settings or click Load to import a .set file. Pay particular attention to lot size and risk.

   Mark as done: Set the inputs
7. 7

   Step 7: Enable AutoTrading

   Click OK and make sure the AutoTrading button on the main toolbar is on. The EA's name appears in the chart's top-right corner with an icon showing whether it may trade.

   Mark as done: Enable AutoTrading

Troubleshooting

The EA isn't in the Navigator

It must be an .ex4 inside MQL4\Experts of the data folder. Refresh the Navigator or restart MT4.

Error 4109 in the Experts tab

Trading isn't allowed: switch on the toolbar AutoTrading button and tick Allow live trading in the EA's properties (F7).

"DLL calls are not allowed"

Enable Allow DLL imports for this EA — only if you trust its developer.