If you’ve created a script or imported somebody else’s MetaTrader script into your Experts folder and upon dragging the Expert Advisor notice that it doesn’t attach to the chart.

Upon further inspection you notice in the Experts tab the following warnings:

Cannot open file ex4 error

Cannot open file ex4 error

Why does my Expert Advisor not load?

The reason why your Expert Advisor is failing to load and throwing up this oblique error about cannot open file is because of one primary reason: your code has not compiled correctly. The most obvious way to fix this code is open it up and just click F5 on your keyboard, or the Compile button in the middle of the editor:

Compile your code by hitting F5 on your keyboard, or click on the Compile button

Compile your code by hitting F5 on your keyboard, or click on the Compile button

Still get the error?

If you still get the error then after you’ve compiled your code look very carefully at the Errors output window down in the Toolbox area, mine showed the following:

Check MetaEditor’s Toolbox Error pane carefully

Check MetaEditor’s Toolbox Error pane carefully

The problem with my Toolbox window pane is your eyes may glaze over the icons, and if you don’t see any red error circles you fail to read the prompt at the bottom which states there is an error with your code:

Therefore, you’ll need to scroll up and fix the error issues:

Scroll your error pane up to spot the error

Scroll your error pane up to spot the error

Then once you’ve fixed the error you should be able to successfully compile your code.

While you’re at it, you may as well clean up all the warnings too as they mask the important error warnings which prevent you from compiling your forex trading code.

Conclusion

In this article you’ve discovered how to fix your MetaTrader 4 code upon getting the famous cannot open file ex4 error.

While compiling your code is as easy as hitting F5 on your keyboard, or clicking the Compile button in the editor, you need to make sure there is nothing preventing your code from compiling such as an error in your logic or syntax.