This report aims to provide an in-depth investigation into the EX4 to MQ4 Decompiler 5.0.1 EXE link, a software tool used to decompile MetaTrader 4 (MT4) expert advisors (EAs) and indicators from EX4 files back into their source MetaQuotes 4 (MQ4) code. The tool has gained attention among traders and developers for its capability to reverse-engineer compiled MT4 files. This investigation will examine the functionality, legality, and implications of using such a tool.