Indicates the start of an InstallMate session. Clients should use this opportunity to perform any global initialization and, if necessary, use pMessage->lCookie to let InstallMate maintain additional state between messages. pMessage->dwSessionType indicates the type of session that is about to start. Any associated cleanup should be performed during TIXMSG_TERMINATE.

Action scheduling

This message is sent as soon as the extension DLL is loaded and before the UI is created. Therefore, your handler should not rely on the availability of a main window and in fact should not display any message boxes, dialogs, or windows at all.

This message is also sent during preflight checks when InstallMate builds the installer.


Not used

Result code

If this message is handled, pMessage->lResult must be set to one of the following result codes: