Fixing common Visual Basic (VB/VB6) Tab Control ActiveX runtime errors usually requires re-registering the MSCOMCTL.OCX or TABCTL32.OCX component files using the Windows command prompt with administrator privileges. These errors occur when the legacy 32-bit Tab Control components used in VB projects lose their registry associations, encounter versioning conflicts, or miss background security permissions on modern Windows operating systems. Common Tab-Control Runtime Errors
Run-time error ‘429’: ActiveX component can’t create object – This occurs when the OS cannot find or instantiate the control’s component class in the Windows Registry.
Run-time error ‘372’: Failed to load control… – This happens when the version of the .ocx file on the machine is older than what the compiled VB application expects.
Component ‘MSCOMCTL.OCX’ or ‘TABCTL32.OCX’ not correctly registered – This indicates a broken file path or a missing file in the system directory. Step-by-Step Fixes 1. Re-Register the ActiveX Control File
This is the most frequent fix for ActiveX runtime issues. You must execute this using the 32-bit subsystem command line on 64-bit Windows machines. Press the Windows Key and type cmd. Right-click Command Prompt and choose Run as Administrator.
For a 64-bit Windows operating system, type the following command to navigate to the 32-bit library folder and press Enter: cd C:\Windows\SysWOW64 Use code with caution.
(Note: If you are running an old 32-bit Windows OS, use cd C:\Windows\System32 instead).
Type the registration command for the specific tab control and press Enter: regsvr32 mscomctl.ocx Use code with caution. or regsvr32 tabctl32.ocx Use code with caution.
Look for a popup window confirming DIlRegisterServer in [filename] succeeded. 2. Resolve Binary Version Conflicts (For Developers)
If your application runs perfectly in the VB6 IDE but crashes with Error 372 on user machines, you are hitting version compatibility limits.
Set Binary Compatibility: In the VB6 IDE, go to Project > Properties > Component tab. Set the version compatibility to Binary Compatibility to keep the unique interface identifiers (GUIDs) identical across every build.
Update the Project File: Open your .vbp project file in a text editor like Notepad. Ensure the GUID string matching Object={…} points exactly to the active version of MSCOMCTL.OCX or TABCTL32.OCX installed on the test machine. 3. Install the VB6 Runtime Redistributable Package
Modern Windows systems do not ship with full developer runtime libraries enabled by default.
Ensure target client machines have the Microsoft Visual Basic 6.0 Service Pack 6 Runtime Redistributable installed to supply all standard dependencies. 4. Configure Modern Security & Scaling Safeguards
ActiveX is heavily restricted in modern execution environments.
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