The OCA file extension can be found in other file types. The format was developed by Microsoft. The file was likely created in Microsoft Visual Basic.
Associate the OCA file extension with the application that should open custom control libraries. Update the software that actually opens OCA files. Only current versions support the latest OCA format.
The ICO file extension is for image files used as icons in Windows. ICO files are packaged in icon libraries for Windows. Windows Vista does not display icons from old 16-bit libraries.
OKA files are somewhat common. Issues opening them can be from corrupt or outdated device drivers. Or inadequate system resources.
The OVA file extension is used by virtual appliances in VMware and VirtualBox. It packages files describing a virtual machine. The OVA file uses the open virtualization format standard.
The OCE file extension is an Oracle standard. OCE files work on Windows devices. Brio software manages OCE files.
The IOCA file extension should associate with the correct software. If an IOCA file is not infected, antivirus software may block it. Take precautions suggested by the system.