MSCOMCTL.OCX Could Not Be Loaded in VB6 Examples

If one of the SocketTools VB6 example projects fails to open because MSCOMCTL.OCX cannot be loaded, the system typically has an older version of the Microsoft Common Controls library installed. This article explains why the error occurs, which controls are affected, and how to resolve the problem using Microsoft’s supported update package. The Microsoft update is the recommended fix because it installs the correct version of the controls and registers them properly. If the update is already installed and the project still will not load, the troubleshooting steps below can help isolate registration, version, or deployment issues.

Symptoms

When the problem occurs, Visual Basic 6 may display an error such as:

C:\Windows\SysWOW64\MSCOMCTL.OCX could not be loaded

Depending on the project and system configuration, the example project may fail to load entirely or may open with missing references for one or more common controls.

The issue most often affects projects that use controls such as:

• ListView
• TreeView
• ImageList
• Toolbar
• StatusBar
• ProgressBar

Cause

This issue is usually caused by a version mismatch between the control installed on the local system and the version referenced by the project file. Microsoft provides an update for the Visual Basic 6.0 common controls included with Service Pack 6, including MSCOMCTL.OCX and COMCTL32.OCX.

Projects created or updated on a machine with newer common controls installed may reference a control version that is not available on another development system. When that happens, VB6 can reject the project reference and stop loading the project correctly.

A typical example is a project file that references a newer revision of MSCOMCTL.OCX than the target system has installed. For example, the project file may contain a line similar to the following:

Object={831FDD16-0C5C-11D2-A9FC-0000F8754DA1}#2.2#0; MSCOMCTL.OCX

If another system only has an older revision of the control installed, Visual Basic 6 may reject the reference and report that the control cannot be loaded.

Resolution

The supported resolution is to install Microsoft's updated Common Controls package. Microsoft distributes the package as VB60SP6-KB3096896-x86-ENU.msi, which updates the Visual Basic 6.0 common controls used by projects such as these.

Download the package from Microsoft, install it, and then restart Visual Basic 6 before reopening the project.

Microsoft download page: https://www.microsoft.com/en-us/download/details.aspx?id=50722

Verify the Installed Version

After installing the update, confirm that the expected control version is present on the development system. On 64-bit versions of Windows, check the file shown below:

C:\Windows\SysWOW64\MSCOMCTL.OCX

The updated file should report version 6.1.98.46, which matches the Microsoft package details and commonly resolves this project load error. You may also see a file date of November 5, 2015.

What Not to Do

Although it is technically possible to edit the .vbp file and change the project reference to an earlier control version, that approach is generally not recommended.

• The project may rely on functionality present in the newer controls
• Binary compatibility problems can occur
• Older control versions may contain known security vulnerabilities

For most developers, installing Microsoft’s update package is the safest and most reliable solution.

Troubleshooting

If the update is already installed and the project still will not load, start by confirming that the control is installed in the correct system folder and registered properly. On 64-bit Windows, the 32-bit control should normally be located in C:\Windows\SysWOW64; on 32-bit Windows, it should normally be in C:\Windows\System32. If the file exists but the error persists, re-register it from an elevated command prompt using regsvr32. Errors such as 0x8002801C usually indicate the command was not run with administrative rights.

If the project file still references the wrong control version, compare the Object= line in the .vbp file with a working project on the same machine. In some cases, removing NoControlUpgrade=1 allows VB6 to update the reference. If the error mentions missing dependencies rather than only the OCX itself, repair or reinstall the development environment before making manual file changes.

Avoid manually copying MSCOMCTL.OCX from another system unless you are only using it as a temporary diagnostic step. Simply copying the file can lead to incorrect registration information, version mismatches, missing dependencies, and future servicing problems. The official Microsoft package is the preferred way to install and register the control correctly.

Additional Information

This issue is most often seen on older development systems or clean environments where the newer Visual Basic 6 common controls update has not yet been installed.

• Older Visual Basic 6 development systems
• Newly created virtual machines
• Offline build environments
• Systems installed from original VB6 media without later runtime updates

Although Visual Basic 6 is a legacy development environment, Microsoft still provides the control update needed for compatibility with many existing projects. If you are using the SocketTools VB6 examples on a newly configured system, installing the current common controls package should usually resolve the problem quickly.

See Also

DllRegisterServer Fails with Error 0x80040200
ActiveX Component Can’t Create Object