Application structure
Forms, modules, classes, procedures, event handlers, and known runtime relationships provide a map of the project.
Legacy project recovery
Recover Lost VB6 Source Code from EXE, DLL and OCX Files
A compiled file cannot contain every detail of the original project, but it can still preserve enough code behavior, forms, controls, events, strings, APIs, and resources to rebuild a maintainable replacement.
What can usually be recovered
Executable behavior
P-Code or native x86 can be reconstructed into analyst-oriented code in licensed editions, with disassembly available alongside it.
User interface
Form layouts, standard controls, properties, and event bindings can be inspected visually and exported as recovery material.
Data and resources
Strings, icons, images, FRX resources, API usage, and references help restore both interface and logic.
What the recovered code really means
The output is not a ready-to-compile copy of the lost VB5/6 project. VB Decompiler recovers up to 85% of code from typical supported P-Code and Native Code applications, which is close to the practical limit for offline static recovery. The remaining portion may contain incompatible syntax, incorrectly inferred expressions, missing types, or fragments that still need manual reverse engineering. Opening the recovered material in the VB5/6 IDE can therefore produce many compile errors until a developer corrects and reconnects it.
Comments, original formatting, meaningful local-variable names, and source-only design decisions are generally absent after compilation. Forms, event relationships, strings, APIs, disassembly, and references provide the evidence needed to repair the reconstruction, but this is still software-development work.
The approximate 85% figure is not a guarantee for an individual file. Obfuscation, protection, damage, unusual controls, and compiler-specific patterns can lower recovery.
Improve the result with AI Helper
VB Decompiler's AI Helper can pass selected decompiled code through prepared prompts to a local offline model or through the OpenAI API. AI can explain difficult fragments, propose names, simplify control flow, and help convert the recovered output into cleaner VB5/6 or migration code. Its suggestions still need developer review and validation against the binary.
A practical recovery sequence
- Work from a copy and preserve the original binary and its hash.
- Identify P-Code versus Native Code; the two formats require different reconstruction strategies.
- Recover forms, controls, project objects, procedures, strings, and resources before rewriting anything.
- Follow event links and call references to reconnect interface behavior with code.
- Rename recovered variables and functions as their roles become clear. Use AI Helper when appropriate to turn analyst notes and decompiled output into clearer code.
- Create a new VB6 project and test recovered behavior incrementally instead of expecting a one-click recompilation of the original.
Pick the branch that matches your code
Begin with the binary you still have
Lite can identify the format, show disassembly, and recover the visual portion of VB5/6 forms. Choose a paid edition only when you know which code-recovery features the project needs.