A DLL file is a shared library used by Windows applications to perform specific tasks. Unlike standard executable (.exe) files, DLLs cannot be run directly; instead, they are loaded by applications at runtime to provide reusable functions and resources. This modular architecture saves system memory by allowing multiple programs to use the same library simultaneously.

Before choosing a tool, you must know what "flavor" of code is inside the DLL.

These tools are highly effective and can often recover near-perfect source code. What Is ILSpy? A Complete Guide to the .NET Decompiler

Several tools are available for decompiling DLL files. Here are some of the most popular ones:

Dynamic Link Libraries (DLLs) are the workhorses of the Windows operating system and countless applications. They contain code, resources, and data that multiple programs can use simultaneously. But what happens when you lose the original source code? What if you need to debug a legacy application, recover lost work, or analyze malware?

Decompiled code has endless goto statements.

de4dot cleaned.dll -p unk -r myObfuscated.dll -o myCleaned.dll