Free decompilers fail completely on protected files.
Most "free decompiler" executables are actually Trojans or malware designed to steal your trading account credentials or install keyloggers. Free Ex4 To Mq4 Decompiler Software Applications
The search for "free" decompiler software frequently leads to malicious websites. Free decompilers fail completely on protected files
Finding a reliable is extremely difficult because MetaTrader 4 (MT4) updated its compilation methods in 2014. Most "free" software found today either only works on outdated builds (build 509 or older) or is categorized as high-risk malware. The Reality of EX4 to MQ4 Decompilation Free Ex4 To Mq4 Decompiler Software Applications
The most critical aspect of this report is the security risk associated with obtaining free decompilers from unverified sources.