File Extension

A File Extension object represents a file extension registration or unregistration. It is a child of a File Type and is used to associate file names with file types and, through that, with applications that can open them. Registration or unregistration of a file extension is controlled by its component and its parent file type.

Situation InstallMate
Not linked to a component The file extension is registered if its parent file type is registered.
Linked to a component The file extension is registered if its component is installed.*

*This in turn may cause its parent File Type to be installed.

See File types for more information.


The following attributes and options are available.

Attribute Description
Extension Enter the file extension, including the the leading period.
MIME type

Enter the MIME type for the file extension, or leave empty to omit the MIME type association. If you do specify a MIME type you should also create a separate MIME Type registration, unless the MIME type is a standard type that is preregistered on the target system.

Perceived type

Select the perceived type of the file extension from the drop-down list, or enter your own type. Windows XP and later use the perceived type as a kind of generic file type to provide common shell functionality to classes of files, instead of individual file types.

The drop-down list contains the generic types that are predefined by Windows XP, but you are free to enter your own. In that case, you may want to add the new type to the HKCR\SystemFileAssociations registry key; use the Registry project page to do so. Consult the Microsoft Windows Platform SDK documentation for more information about perceived type registration.

Tip: If you do not want to register a perceived type for the file extension, then clear this field.

Related topics

File types, Working with attribute panes