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Run the free VBScanner on the folder. It reads the file headers and tells you what built each EXE, DLL or OCX and whether it is P-Code, native or IL.
Unless a developer switched the project to native code, Visual Basic 5 and 6 compiled to P-Code: a stream of tokens that the runtime interprets at run time. That stream keeps far more of the original structure than machine code does, and our P-Code decompiler decodes it procedure by procedure into readable Basic — not a token dump — inside the same rebuilt project you get for native VB6.
See a real P-Code recovery, Miner VGA, next to its original source →
A P-Code build imports only the runtime's interpreter entry points, ProcCallEngine
and MethCallEngine, and keeps each procedure as a sequence of opcodes: push this
value, call that method, compare, branch. The runtime executes them one at a time. Because the
opcodes are the compiler's own intermediate language, they still say what the code does
rather than how the processor should do it.
The decompiler runs those opcodes through a stack machine of its own, tracking operands as
it goes, and emits Basic as each statement completes. Post-passes then restore the shape a
programmer wrote: ElseIf cascades, Do loops, For /
Next, Select Case including Case lo To hi ranges,
On Error Resume Next, On Error GoTo 0 and labelled handlers,
Property Get / Let / Set, Type blocks and
absolute module globals. Events are matched to their controls from the control name and the
event interface, so cmdOK_Click lands on the right button.
Every procedure decoded to Basic, with the raw token and opcode listing available alongside for anyone who wants to verify the work.
Forms with controls and .frx resources, modules, classes, user controls, property pages and designers, in a .vbp that opens in VB6.
On Error forms, Property Get / Let / Set, user-defined types and constant substitution come back in place.
All 83 event-handler names recovered on our largest P-Code benchmark, each attached to its form and control.
| Benchmark | Metric | Then → now |
|---|---|---|
| Areena5.exe (1.82 MB game) | Procedures decoded | 496 of 496, 0 undecoded opcodes |
Uncompilable Unknown GUID references | 97 → 0 | |
| Lost operands | 332 → 10 | |
| Fabricated literals | 120 → 0 | |
| Forms with a balanced designer | 7 of 7 | |
| DNManagerPro.exe | Modules with correct names | 22 of 22 |
| Procedures recovered vs source | 218 of 219 | |
On Error Resume Next restored | 30 of 31 | |
Declare statements | 35 of 38 |
Form, control, class and event-handler names, module names and Declare signatures are kept.
Standard-module procedure names are not: their name tables are empty in the EXE, so
module procedures come back as Proc0040A1C0-style placeholders. Projects that use
only late binding carry no Reference= data for the type libraries they touch, and a
property value that equals the control's default cannot be told apart from one that was never
set. Comments are never compiled.
Run the free VBScanner on the folder. It reads the file headers and tells you what built each EXE, DLL or OCX and whether it is P-Code, native or IL.
License the software — $299 for one computer or $1,499 for your whole organization with the command line — and run it on your own machine. Nothing leaves your network.
Request a free evaluation. We examine the binary, tell you exactly what comes back, and quote a fixed price and timeline. Hand-finishing of anything the engine marks is included.
Run the free VBScanner on it. It reads the VB5! header and reports P-Code or native for every EXE, DLL and OCX in a folder. The software reports the same thing in its File Report.
Yes. P-Code is the compiler's own intermediate language, so conditions, loops and calls decode directly; native code has to be reconstructed from machine instructions. Both engines produce the same project layout, but P-Code output usually needs less clean-up.
Yes. VB5 and VB6 share the VB5! header and the same P-Code design; the runtime is MSVBVM50 instead of MSVBVM60. See the VB5 decompiler page for the differences.
The evaluation is free and tells you exactly what your binary yields before you spend anything. Or license the decompiler and run it in-house today.