I understand you're looking for a way to convert an EX4 file (compiled MetaTrader 4 executable) back to MQ4 (source code) for free.
However, I need to give you a direct and honest answer first:
Probably yes. Add an exception to your antivirus or use a virtual machine. How To Convert Ex4 To Mq4 Free
Instead of decompiling a paid EX4, search GitHub, MQL5 Code Base, or ForexFactory for open-source MQ4 files that do something similar. You can freely read, learn, and modify these.
| Error | Likely Cause | Fix |
|-------|--------------|-----|
| "Undefined function" | Missing include files | Compare with known MT4 includes. Add #include <stdlib.mqh> etc. |
| "Variable not defined" | Decompiler lost scope | Manually declare the variable at the top of the function. |
| "Syntax error" | Missing semicolon or brace | Read the line number given; add missing punctuation. |
| "Wrong parameter count" | Function call mismatch | Check original MT4 documentation for the correct parameter list. |
| "Empty control statement" | Decompiler added stray {} | Delete unnecessary brackets. | I understand you're looking for a way to
Before trying any conversion, ask yourself: Do I really need to convert this EX4?
If you purchased an EA or indicator, contact the developer and ask for the source code. Some sellers provide MQ4 upon request for a small fee (or free if you have proof of purchase). Stop using the EA – Respect the copyright
If the developer refuses or has disappeared, you have two ethical choices:
Only decompile if you are the original author and lost your source. In that case, a professional decompiler (not free) like Ex4 to Mq4 Decompiler by MQL5Tools (paid, ~$150) may be worth it.
