Home/ Questions/Q 3356078
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-18T02:28:18+00:00

In the system32 directory I saw an .OCX file with a corresponding .OCA file.

  • 0

In the system32 directory I saw an .OCX file with a corresponding .OCA file.

I had thought .OCA files are used only by Visual Basic. Are they therefore unnecessary for program execution and could be removed?

If they are unnecessary, why would there be an .OCA in the system32 folder in the first place?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    .OCA files serve as a cache of the extended type library information for its corresponding .OCX file.

    If you delete an .OCA file for a control VB recognizes and uses, VB will recreate the .OCA file when you load a project requiring the control. The recreation process takes a little time but comes with no penalty otherwise.

    Last reviewed: April 4, 1996

    Article ID: Q149429

    SUMMARY For every custom control file (.OCX) that Visual Basic uses,
    there is an accompanying .OCA file of the same file name. For example,
    GRAPH16.OCX has an accompanying .OCA file called GRAPH16.OCA. An .OCA
    file is a binary file that functions as both an extended type library
    file and a cache for the custom control file.

    MORE INFORMATION

    A type library is a file or component within another
    file that contains OLE Automation standard descriptions of exposed
    objects, properties, and methods. The actual working type library for
    a custom control used in Visual Basic is a combination of the type
    library of the control itself and the additional properties provided
    by the framework that wrap the control.

    Some of the properties of the control are provided by the framework
    and some by the control itself. Programmatically, the properties from
    the framework and the control all appear as properties of the control.

    In order for these properties to appear, Visual Basic creates an
    extended type library when the control is loaded into the toolbox.
    Because the process of reading the control’s type library and creating
    the extended type library is time consuming, Visual Basic caches the
    extended type library information into an OCA file.

    If you delete the OCA file for a control Visual Basic recognized,
    Visual Basic will re-create the .OCA file when you load a project
    requiring the control. This re-creation process comes with a time
    penalty.

    (http://support.microsoft.com/kb/149429)

    So, don’t worry about including them when you deploy your application.

    • 0