Decompiled code is rarely "clean." Variable names are usually lost (replaced with things like var1 , var2 ), and the logic can be fragmented, making it nearly impossible to optimize without a deep understanding of MQL4. The Best Alternative: MQL4 Coding Services

: Simple "drag-and-drop" interface to generate an MQ4 file in the same directory.

This is the biggest danger. Forex traders are a prime target for hackers. When you search for "Free Decompiler," you are likely downloading a virus.