Add file extension

File extension OCA

The most common cause of problems with opening the OCA file is simply the lack of appropriate applications installed on your computer. In this case, it is sufficient to find, download and install an application that supports the OCA file format - this type of programs are available below.

File type Custom Control Library Type Format
Developer Microsoft



It should be noted that some coded data from files that your computer does not read can be sometimes previewed in a Notepad. This way, we will read passages of a text or numbers. It is worth checking if this method can also be applied to the OCA files.

What should be done when an application from the list has already been installed?

Often, an installed application should automatically link to a OCA file. If it did not happen, the OCA file can be linked with the newly installed application manually. Simply right-click on the OCA file, then from the available list select "Choose default program". Next, select "Browse" and find the application you selected. These changes have to be confirmed by pressing the "OK" button.

Programs that can open the OCA file

  • Visual StudioVisual Studio
  • Microsoft Visual BasicMicrosoft Visual Basic

Why can’t I open the OCA file?

However, problems with the OCA files can also have a different background. Sometimes even the software, installed on your computer, that supports the OCA files does not solve the problem. The reason for the fact that the OCA file can’t be opened and used can also be:

- an incorrect link to the OCA file in the registry entries
- corruption of a OCA file, that you want to open
- infection of a OCA file (viruses)
- insufficient computer hardware resources
- drivers out of date
- accidental deletion of the OCA file from the Windows registry
- incomplete installation of the program that supports a OCA file?

Solving these problems should allow the free opening and working with the OCA files. If the computer still has problems with the files, use the services of an expert who will diagnose a specific cause.

My computer does not show file extensions, what should I do?

In the standard Windows settings, a computer user cannot see the OCA file extension. However, you can successfully change this in the settings. Just go to "Control Panel" and select "Appearance and Personalization". Then, go to the "Folder Options" and open the "View" tab. On the "View" tab, you will find "Hide extensions for known file types" – you should mark this option and confirm by pressing "OK". At this point, the extension of all files, including the OCA files should be displayed after the file name.